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1.
Nat Mater ; 22(4): 511-523, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36928381

RESUMO

Activated B-cell-like diffuse large B-cell lymphomas (ABC-DLBCLs) are characterized by constitutive activation of nuclear factor κB driven by the B-cell receptor (BCR) and Toll-like receptor (TLR) pathways. However, BCR-pathway-targeted therapies have limited impact on DLBCLs. Here we used >1,100 DLBCL patient samples to determine immune and extracellular matrix cues in the lymphoid tumour microenvironment (Ly-TME) and built representative synthetic-hydrogel-based B-cell-lymphoma organoids accordingly. We demonstrate that Ly-TME cellular and biophysical factors amplify the BCR-MYD88-TLR9 multiprotein supercomplex and induce cooperative signalling pathways in ABC-DLBCL cells, which reduce the efficacy of compounds targeting the BCR pathway members Bruton tyrosine kinase and mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1). Combinatorial inhibition of multiple aberrant signalling pathways induced higher antitumour efficacy in lymphoid organoids and implanted ABC-DLBCL patient tumours in vivo. Our studies define the complex crosstalk between malignant ABC-DLBCL cells and Ly-TME, and provide rational combinatorial therapies that rescue Ly-TME-mediated attenuation of treatment response to MALT1 inhibitors.


Assuntos
Linfoma Difuso de Grandes Células B , Microambiente Tumoral , Humanos , Linhagem Celular Tumoral , Transdução de Sinais , NF-kappa B/metabolismo , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/metabolismo , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa/metabolismo
2.
J Mol Cell Cardiol ; 176: 98-109, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36764383

RESUMO

RATIONALE: The innate immune response contributes to cardiac injury in myocardial ischemia/reperfusion (MI/R). Neutrophils are an important early part of the innate immune response to MI/R. Adenosine, an endogenous purine, is a known innate immune modulator and inhibitor of neutrophil activation. However, its delivery to the heart is limited by its short half-life (<30 s) and off-target side effects. CD39 and CD73 are anti-inflammatory homeostatic enzymes that can generate adenosine from phosphorylated adenosine substrate such as ATP released from injured tissue. OBJECTIVE: We hypothesize that hydrogel-delivered CD39 and CD73 target the local early innate immune response, reduce neutrophil activation, and preserve cardiac function in MI/R injury. METHODS AND RESULTS: We engineered a poly(ethylene) glycol (PEG) hydrogel loaded with the adenosine-generating enzymes CD39 and CD73. We incubated the hydrogels with neutrophils in vitro and showed a reduction in hydrogen peroxide production using Amplex Red. We demonstrated availability of substrate for the enzymes in the myocardium in MI/R by LC/MS, and tested release kinetics from the hydrogel. On echocardiography, global longitudinal strain (GLS) was preserved in MI/R hearts treated with the loaded hydrogel. Delivery of purinergic enzymes via this synthetic hydrogel resulted in lower innate immune infiltration into the myocardium post-MI/R, decreased markers of macrophage and neutrophil activation (NETosis), and decreased leukocyte-platelet complexes in circulation. CONCLUSIONS: In a rat model of MI/R injury, CD39 and CD73 delivered via a hydrogel preserve cardiac function by modulating the innate immune response.


Assuntos
Isquemia Miocárdica , Traumatismo por Reperfusão Miocárdica , Ratos , Animais , Hidrogéis/uso terapêutico , Coração , Miocárdio , Adenosina , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Polietilenoglicóis/uso terapêutico
3.
Am J Transplant ; 23(11): 1709-1722, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37543091

RESUMO

The induction of operational immune tolerance is a major goal in beta-cell replacement strategies for the treatment of type 1 diabetes. Our group previously reported long-term efficacy via biomaterial-mediated programmed death ligand 1 (PD-L1) immunotherapy in islet allografts in nonautoimmune models. In this study, we evaluated autoimmune recurrence and allograft rejection during islet transplantation in spontaneous nonobese diabetic (NOD) mice. Graft survival and metabolic function were significantly prolonged over 60 days in recipients of syngeneic islets receiving the biomaterial-delivered immunotherapy, but not in control animals. The biomaterial-mediated PD-L1 immunotherapy resulted in delayed allograft rejection in diabetic NOD mice compared with controls. Discrimination between responders and nonresponders was attributed to the enriched presence of CD206+ program death 1+ macrophages and exhausted signatures in the cytotoxic T cell compartment in the local graft microenvironment. Notably, draining lymph nodes had similar remodeling in innate and adaptive immune cell populations. This work establishes that our biomaterial platform for PD-L1 delivery can modulate immune responses to transplanted islets in diabetic NOD mice and, thus, can provide a platform for the development of immunologic strategies to curb the allo- and autoimmune processes in beta-cell transplant recipients.


Assuntos
Diabetes Mellitus Tipo 1 , Transplante das Ilhotas Pancreáticas , Camundongos , Animais , Camundongos Endogâmicos NOD , Antígeno B7-H1 , Rejeição de Enxerto/etiologia , Diabetes Mellitus Tipo 1/terapia , Imunoterapia , Sobrevivência de Enxerto
4.
Biotechnol Bioeng ; 120(6): 1694-1701, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36810983

RESUMO

We describe a facile strategy to identify sites for the incorporation of noncanonical amino acids into lysostaphin-an enzyme that degrades the cell wall of Staphylococcus aureus-while retaining stapholytic activity. We used this strategy to generate active variants of lysostaphin incorporating para-azidophenylalanine. The incorporation of this "reactive handle" enabled the orthogonal site-specific modification of the enzyme variants with polyethylene glycol (PEG) using copper-free click cycloaddition. PEGylated lysostaphin variants could retain their stapholytic activity, with the extent of retention depending on the site of modification and the PEG molecular weight. The site-specific modification of lysostaphin could be useful not only for PEGylation to improve biocompatibility but also for the incorporation of the enzyme into hydrogels and other biomaterials and for studies of protein structure and dynamics. Moreover, the approach described herein could be readily applied to identify suitable sites for the incorporation of reactive handles into other proteins of interest.


Assuntos
Lisostafina , Infecções Estafilocócicas , Humanos , Lisostafina/farmacologia , Aminoácidos/química , Proteínas , Staphylococcus aureus/metabolismo
5.
Proc Natl Acad Sci U S A ; 117(17): 9477-9482, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32300016

RESUMO

Resolution of intestinal inflammation and wound repair are active processes that mediate epithelial healing at mucosal surfaces. Lipid molecules referred to as specialized proresolving mediators (SPMs) play an important role in the restorative response. Resolvin E1 (RvE1), a SPM derived from omega-3 fatty acids, has been reported to dampen intestinal inflammation by promoting anti-inflammatory responses including increased neutrophil spherocytosis and macrophage production of IL-10. Despite these observations, a role for RvE1 in regulating intestinal epithelial cell migration and proliferation during mucosal wound repair has not been explored. Using an endoscopic biopsy-based wound healing model, we report that RvE1 is locally produced in response to intestinal mucosal injury. Exposure of intestinal epithelial cells to RvE1 promoted wound repair by increasing cellular proliferation and migration through activation of signaling pathways including CREB, mTOR, and Src-FAK. Additionally, RvE1-triggered activation of the small GTPase Rac1 led to increased intracellular reactive oxygen species (ROS) production, cell-matrix adhesion, and cellular protrusions at the leading edge of migrating cells. Furthermore, in situ administration of RvE1-encapsulated synthetic targeted polymeric nanoparticles into intestinal wounds promoted mucosal repair. Together, these findings demonstrate that RvE1 functions as a prorepair lipid mediator by increasing intestinal epithelial cell migration and proliferation, and highlight potential therapeutic applications for this SPM to promote mucosal healing in the intestine.


Assuntos
Ácido Eicosapentaenoico/análogos & derivados , Mucosa Intestinal/metabolismo , Cicatrização/fisiologia , Animais , Adesão Celular , Linhagem Celular , Colo , Ácido Eicosapentaenoico/metabolismo , Ácido Eicosapentaenoico/farmacologia , Humanos , Mucosa Intestinal/patologia , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas , Neuropeptídeos , Organoides , Espécies Reativas de Oxigênio , Proteínas rac1 de Ligação ao GTP
6.
Rev Esp Enferm Dig ; 115(11): 652-653, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36719345

RESUMO

Bariatric endoscopy treats obesity as a disease, in addition to its multiple associated comorbidities, so it should be considered in the "care-curative" field and not as "satisfying, voluntary or outcoming" medicine. Insufficient weight loss cases, or complications may occur. This, in parallel with the greater diffusion of these techniques, results an increase in the risk of complaints and judicial claims, which will presumably grow during next years. In this sense, we consider that all Bariatric Endoscopic Units working with medical-scientific rigor, must be able to be accredited and have legal support by the Scientific Societies. We propose to create a Medical-Legal Advisory Committee, composed of a medical team and a specialized law firm, which allows advising and guiding the endoscopist when incurring in a conflict.


Assuntos
Cirurgia Bariátrica , Bariatria , Obesidade Mórbida , Humanos , Cirurgia Bariátrica/métodos , Endoscopia Gastrointestinal/métodos , Endoscopia/métodos , Obesidade/cirurgia , Redução de Peso
7.
Rev Esp Enferm Dig ; 115(1): 22-34, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36426855

RESUMO

BACKGROUND: intragastric balloons (IGBs) are a minimally invasive, increasingly popular option for obesity treatment. However, there is only one worldwide guideline standardizing the technical aspects of the procedure (BIBC, SOARD 2018). OBJECTIVES: to construct a practical guideline for IGB usage by reproducing and expanding the BIBC survey among the Spanish Bariatric Endoscopy Group (GETTEMO). METHODS: a 140-question survey was submitted to all GETTEMO members. Twenty-one Spanish experienced endoscopists in IGBs answered back. Eight topics on patient selection, indications/contraindications, technique, multidisciplinary follow-up, results, safety, and financial/legal aspects were discussed. Consensus was defined as consensus ≥ 70 %. RESULTS: overall data included 20 680 IGBs including 12 different models. Mean age was 42.0 years-old, 79.9 % were women, and the mean preoperative body mass index (BMI) was 34.05 kg/m². Indication in BMI > 25 kg/m², 10 absolute contraindications, and nutritional and medication measures at follow-up were settled. A mean %TBWL (total body weight loss) of 17.66 % ± 2.5 % was observed. Early removal rate due to intolerance was 3.62 %. Adverse event rate was 0.70 % and 6.37 % for major and minor complications with consensual management. A single case of mortality occurred. IGBs were placed in private health, prior contract, and with full and single payment at the beginning. Seven lawsuits (0.034 %) were received, all ran through civil proceeding, and with favorable final resolution. CONCLUSIONS: this consensus based on more than 20 000 cases represents practical recommendations to perform IGB procedures. This experience shows that the device leads to satisfactory weight loss with a low rate of adverse events. Most results are reproducible compared to those obtained by the BIBC.


Assuntos
Balão Gástrico , Obesidade Mórbida , Humanos , Feminino , Adulto , Masculino , Balão Gástrico/efeitos adversos , Endoscopia Gastrointestinal , Consenso , Redução de Peso , Índice de Massa Corporal , Obesidade Mórbida/cirurgia , Resultado do Tratamento
8.
Small ; 18(36): e2106896, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35274457

RESUMO

Hydrogel microparticles (microgels) are an attractive approach for therapeutic delivery because of their modularity, injectability, and enhanced integration with the host tissue. Multiple microgel fabrication strategies and chemistries have been implemented, yet manipulation of microgel degradability and its effect on in vivo tissue responses remains underexplored. Here, the authors report a facile method to synthesize microgels crosslinked with ester-containing junctions to afford tunable degradation kinetics. Monodisperse microgels of maleimide-functionalized poly(ethylene-glycol) are generated using droplet microfluidics crosslinked with thiol-terminated, ester-containing molecules. Tunable mechanics are achievable based on the ratio of degradable to nondegradable crosslinkers in the continuous phase. Degradation in an aqueous medium leads to microgel deformation based on swelling and a decrease in elastic modulus. Furthermore, degradation byproducts are cytocompatible and do not cause monocytic cell activation under noninflammatory conditions. These injectable microgels possess time-dependent degradation on the order of weeks in vivo. Lastly, the evaluation of tissue responses in a subcutaneous dorsal pocket shows a dynamic type-1 like immune response to the synthetic microgels, driven by interferon gamma (IFN-γ ) expression, which can be moderated by tuning the degradation properties. Collectively, this study demonstrates the development of a hydrolytic microgel platform that can be adapted to desired host tissue immune responses.


Assuntos
Microgéis , Ésteres , Hidrogéis , Imunidade , Polietilenoglicóis
9.
Epidemiology ; 33(2): 209-216, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34860727

RESUMO

BACKGROUND: Six months into the COVID-19 pandemic, college campuses faced uncertainty regarding the likely prevalence and spread of disease, necessitating large-scale testing to help guide policy following re-entry. METHODS: A SARS-CoV-2 testing program combining pooled saliva sample surveillance leading to diagnosis and intervention surveyed over 112,000 samples from 18,029 students, staff and faculty, as part of integrative efforts to mitigate transmission at the Georgia Institute of Technology in Fall 2020. RESULTS: Cumulatively, we confirmed 1,508 individuals diagnostically, 62% of these through the surveillance program and the remainder through diagnostic tests of symptomatic individuals administered on or off campus. The total strategy, including intensification of testing given case clusters early in the semester, was associated with reduced transmission following rapid case increases upon entry in Fall semester in August 2020, again in early November 2020, and upon re-entry for Spring semester in January 2021. During the Fall semester daily asymptomatic test positivity initially peaked at 4.1% but fell below 0.5% by mid-semester, averaging 0.84% across the Fall semester, with similar levels of control in Spring 2021. CONCLUSIONS: Owing to broad adoption by the campus community, we estimate that the program protected higher risk staff and faculty while allowing some normalization of education and research activities.


Assuntos
COVID-19 , Teste para COVID-19 , Humanos , Pandemias , Pesquisa , SARS-CoV-2
11.
J Immunol ; 204(10): 2840-2851, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32253240

RESUMO

Allogeneic islet transplantation is limited by adverse effects of chronic immunosuppression used to control rejection. The programmed cell death 1 pathway as an important immune checkpoint has the potential to obviate the need for chronic immunosuppression. We generated an oligomeric form of programmed cell death 1 ligand chimeric with core streptavidin (SA-PDL1) that inhibited the T effector cell response to alloantigens and converted T conventional cells into CD4+Foxp3+ T regulatory cells. The SA-PDL1 protein was effectively displayed on the surface of biotinylated mouse islets without a negative impact islet viability and insulin secretion. Transplantation of SA-PDL1-engineered islet grafts with a short course of rapamycin regimen resulted in sustained graft survival and function in >90% of allogeneic recipients over a 100-d observation period. Long-term survival was associated with increased levels of intragraft transcripts for innate and adaptive immune regulatory factors, including IDO-1, arginase-1, Foxp3, TGF-ß, IL-10, and decreased levels of proinflammatory T-bet, IL-1ß, TNF-α, and IFN-γ as assessed on day 3 posttransplantation. T cells of long-term graft recipients generated a proliferative response to donor Ags at a similar magnitude to T cells of naive animals, suggestive of the localized nature of tolerance. Immunohistochemical analyses showed intense peri-islet infiltration of T regulatory cells in long-term grafts and systemic depletion of this cell population resulted in prompt rejection. The transient display of SA-PDL1 protein on the surface of islets serves as a practical means of localized immunomodulation that accomplishes sustained graft survival in the absence of chronic immunosuppression with potential clinical implications.


Assuntos
Aloenxertos/fisiologia , Antígeno B7-H1/metabolismo , Diabetes Mellitus Tipo 1/imunologia , Terapia de Imunossupressão/métodos , Ilhotas Pancreáticas/fisiologia , Estreptavidina/metabolismo , Linfócitos T Reguladores/imunologia , Animais , Antígeno B7-H1/genética , Diferenciação Celular , Sobrevivência Celular , Fatores de Transcrição Forkhead/metabolismo , Humanos , Tolerância Imunológica , Imunidade/genética , Imunomodulação , Transplante das Ilhotas Pancreáticas , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Proteínas Recombinantes de Fusão/genética , Estreptavidina/genética
12.
Rev Esp Enferm Dig ; 114(5): 300-301, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35034457

RESUMO

Sixty year old female with hypertension and crampy abdominal pain episodes. Admitted to hospital (September-2020) by obstructive jaundice. MRCP: biliary dilation due to Todani Ic (fusiform) choledocal cyst (CC), distal sludge. ERCP: normal mucosa prominent papilla; biliary dilation compatible with CC; choledocholithiasis; 8-mm CHD filling defect. Sphincterotomy, removal of stones/sludge, brush-cytology of the filling defect (pathology: atypias). US: dilation resolution (CBD: 6.5 mm).


Assuntos
Cisto do Colédoco , Coledocolitíase , Colangiopancreatografia Retrógrada Endoscópica , Cisto do Colédoco/complicações , Cisto do Colédoco/diagnóstico por imagem , Cisto do Colédoco/cirurgia , Coledocolitíase/complicações , Coledocolitíase/diagnóstico por imagem , Coledocolitíase/cirurgia , Feminino , Humanos , Esgotos , Esfinterotomia Endoscópica
13.
J Biol Chem ; 295(46): 15438-15453, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-32883809

RESUMO

Widespread testing for the presence of the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals remains vital for controlling the COVID-19 pandemic prior to the advent of an effective treatment. Challenges in testing can be traced to an initial shortage of supplies, expertise, and/or instrumentation necessary to detect the virus by quantitative RT-PCR (RT-qPCR), the most robust, sensitive, and specific assay currently available. Here we show that academic biochemistry and molecular biology laboratories equipped with appropriate expertise and infrastructure can replicate commercially available SARS-CoV-2 RT-qPCR test kits and backfill pipeline shortages. The Georgia Tech COVID-19 Test Kit Support Group, composed of faculty, staff, and trainees across the biotechnology quad at Georgia Institute of Technology, synthesized multiplexed primers and probes and formulated a master mix composed of enzymes and proteins produced in-house. Our in-house kit compares favorably with a commercial product used for diagnostic testing. We also developed an environmental testing protocol to readily monitor surfaces for the presence of SARS-CoV-2. Our blueprint should be readily reproducible by research teams at other institutions, and our protocols may be modified and adapted to enable SARS-CoV-2 detection in more resource-limited settings.


Assuntos
Teste de Ácido Nucleico para COVID-19/métodos , COVID-19/diagnóstico , Kit de Reagentes para Diagnóstico/economia , SARS-CoV-2/genética , Transferência de Tecnologia , Universidades/economia , Biotecnologia/métodos , COVID-19/virologia , Humanos , Kit de Reagentes para Diagnóstico/provisão & distribuição , Reação em Cadeia da Polimerase em Tempo Real/métodos , SARS-CoV-2/isolamento & purificação
14.
J Cell Sci ; 132(20)2019 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-31558679

RESUMO

Synthetic hydrogels with controlled physicochemical matrix properties serve as powerful in vitro tools to dissect cell-extracellular matrix (ECM) interactions that regulate epithelial morphogenesis in 3D microenvironments. In addition, these fully defined matrices overcome the lot-to-lot variability of naturally derived materials and have provided insights into the formation of rudimentary epithelial organs. Therefore, we engineered a fully defined synthetic hydrogel with independent control over proteolytic degradation, mechanical properties, and adhesive ligand type and density to study the impact of ECM properties on epithelial tubulogenesis for inner medullary collecting duct (IMCD) cells. Protease sensitivity of the synthetic material for membrane-type matrix metalloproteinase-1 (MT1-MMP, also known as MMP14) was required for tubulogenesis. Additionally, a defined range of matrix elasticity and presentation of RGD adhesive peptide at a threshold level of 2 mM ligand density were required for epithelial tubulogenesis. Finally, we demonstrated that the engineered hydrogel supported organization of epithelial tubules with a lumen and secreted laminin. This synthetic hydrogel serves as a platform that supports epithelial tubular morphogenetic programs and can be tuned to identify ECM biophysical and biochemical properties required for epithelial tubulogenesis.


Assuntos
Microambiente Celular , Células Epiteliais/metabolismo , Matriz Extracelular/química , Hidrogéis/química , Túbulos Renais Coletores/metabolismo , Túbulos Renais/metabolismo , Animais , Linhagem Celular Transformada , Células Epiteliais/citologia , Túbulos Renais/citologia , Túbulos Renais Coletores/citologia , Metaloproteinase 14 da Matriz/metabolismo , Camundongos , Oligopeptídeos/química
15.
Mol Cell ; 49(6): 1060-8, 2013 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-23416109

RESUMO

Cells regulate adhesion in response to internally generated and externally applied forces. Integrins connect the extracellular matrix to the cytoskeleton and provide cells with mechanical anchorages and signaling platforms. Here we show that cyclic forces applied to a fibronectin-integrin α5ß1 bond switch the bond from a short-lived state with 1 s lifetime to a long-lived state with 100 s lifetime. We term this phenomenon "cyclic mechanical reinforcement," as the bond strength remembers the history of force application and accumulates over repeated cycles, but does not require force to be sustained. Cyclic mechanical reinforcement strengthens the fibronectin-integrin α5ß1 bond through the RGD binding site of the ligand with the synergy binding site greatly facilitating the process. A flexible integrin hybrid domain is also important for cyclic mechanical reinforcement. Our results reveal a mechanical regulation of receptor-ligand interactions and identify a molecular mechanism for cell adhesion strengthening by cyclic forces.


Assuntos
Adesão Celular , Fibronectinas/química , Integrina alfa5beta1/química , Fenômenos Biomecânicos , Fibronectinas/fisiologia , Humanos , Integrina alfa5beta1/fisiologia , Molécula 1 de Adesão Intercelular/química , Molécula 1 de Adesão Intercelular/fisiologia , Células Jurkat , Membranas Artificiais , Microscopia de Força Atômica , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/fisiologia , Poliestirenos/química , Ligação Proteica
16.
Proc Natl Acad Sci U S A ; 115(22): E4960-E4969, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29760099

RESUMO

Orthopedic implant infections are a significant clinical problem, with current therapies limited to surgical debridement and systemic antibiotic regimens. Lysostaphin is a bacteriolytic enzyme with high antistaphylococcal activity. We engineered a lysostaphin-delivering injectable PEG hydrogel to treat Staphylococcus aureus infections in bone fractures. The injectable hydrogel formulation adheres to exposed tissue and fracture surfaces, ensuring efficient, local delivery of lysostaphin. Lysostaphin encapsulation within this synthetic hydrogel maintained enzyme stability and activity. Lysostaphin-delivering hydrogels exhibited enhanced antibiofilm activity compared with soluble lysostaphin. Lysostaphin-delivering hydrogels eradicated S. aureus infection and outperformed prophylactic antibiotic and soluble lysostaphin therapy in a murine model of femur fracture. Analysis of the local inflammatory response to infections treated with lysostaphin-delivering hydrogels revealed indistinguishable differences in cytokine secretion profiles compared with uninfected fractures, demonstrating clearance of bacteria and associated inflammation. Importantly, infected fractures treated with lysostaphin-delivering hydrogels fully healed by 5 wk with bone formation and mechanical properties equivalent to those of uninfected fractures, whereas fractures treated without the hydrogel carrier were equivalent to untreated infections. Finally, lysostaphin-delivering hydrogels eliminate methicillin-resistant S. aureus infections, supporting this therapy as an alternative to antibiotics. These results indicate that lysostaphin-delivering hydrogels effectively eliminate orthopedic S. aureus infections while simultaneously supporting fracture repair.


Assuntos
Antibacterianos/administração & dosagem , Consolidação da Fratura/efeitos dos fármacos , Hidrogéis/uso terapêutico , Lisostafina/administração & dosagem , Infecções Relacionadas à Prótese , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Materiais Biocompatíveis/uso terapêutico , Modelos Animais de Doenças , Fraturas do Fêmur/cirurgia , Lisostafina/farmacologia , Lisostafina/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Desenho de Prótese , Infecções Relacionadas à Prótese/tratamento farmacológico , Infecções Relacionadas à Prótese/prevenção & controle , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus
17.
J Cell Physiol ; 235(6): 5120-5129, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31674663

RESUMO

Dendritic cells are key players in regulating immunity. These cells both activate and inhibit the immune response depending on their cellular environment. Their response to hyperglycemia, a condition common amongst diabetics wherein glucose is abnormally elevated, remains to be elucidated. In this study, the phenotype and immune response of dendritic cells exposed to hyperglycemia were characterized in vitro and in vivo using the streptozotocin-induced diabetes model. Dendritic cells were shown to be sensitive to hyperglycemia both during and after differentiation from bone marrow precursor cells. Dendritic cell behavior under hyperglycemic conditions was found to vary by phenotype, among which, tolerogenic dendritic cells were particularly sensitive. Expression of the costimulatory molecule CD86 was found to reliably increase when dendritic cells were exposed to hyperglycemia. Additionally, hydrogel-based delivery of the anti-inflammatory molecule interleukin-10 was shown to partially inhibit these effects in vivo.


Assuntos
Células Dendríticas/metabolismo , Hiperglicemia/metabolismo , Tolerância Imunológica/genética , Linfócitos T Reguladores/imunologia , Animais , Antígeno B7-2/genética , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Diferenciação Celular/imunologia , Células Dendríticas/patologia , Glucose/metabolismo , Humanos , Hiperglicemia/genética , Hiperglicemia/imunologia , Hiperglicemia/patologia , Tolerância Imunológica/imunologia , Interleucina-10/farmacologia , Camundongos , Linfócitos T Reguladores/patologia
18.
Exp Cell Res ; 377(1-2): 109-114, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30794801

RESUMO

Human organoids provide constructive in vitro models of human development and disease, as these recapitulate important morphogenetic and functional features of the tissue and species of origin. However, organoid culture technologies often involve the use of biologically-derived materials (e.g. Matrigel™) that do not allow dissection of the independent contributions of the biochemical and biophysical matrix properties to organoid development. Additionally, their inherent lot-to-lot variability and, in the case of Matrigel™, tumor-derived nature limits their applicability as platforms for drug and tissue transplantation therapies. Here, we highlight recent studies that overcome these limitations through engineering of novel biomaterial platforms that (1) allow to study the independent contributions of physicochemical matrix properties to organoid development and their potential for translational therapies, and (2) better recreate the tumor microenvironment for high-throughput, pre-clinical drug development. These studies illustrate how innovative biomaterial constructs can contribute to the modeling of human development and disease using organoids, and as platforms for development of organoid-based therapies. Finally, we discuss the current limitations of the organoid field and how they can potentially be addressed using engineered biomaterials.


Assuntos
Materiais Biocompatíveis/química , Diferenciação Celular , Intestinos/citologia , Modelos Biológicos , Neoplasias/terapia , Organoides/citologia , Engenharia Tecidual/métodos , Animais , Descoberta de Drogas , Humanos , Organogênese , Microambiente Tumoral
19.
Am J Transplant ; 19(5): 1315-1327, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30378751

RESUMO

Transplant of hydrogel-encapsulated allogeneic islets has been explored to reduce or eliminate the need for chronic systemic immunosuppression by creating a physical barrier that prevents direct antigen presentation. Although successful in rodents, translation of alginate microencapsulation to large animals and humans has been hindered by large capsule sizes (≥500 µm diameter) that result in suboptimal nutrient diffusion in the intraperitoneal space. We developed a microfluidic encapsulation system that generates synthetic poly(ethylene glycol)-based microgels with smaller diameters (310 ± 14 µm) that improve encapsulated islet insulin responsiveness over alginate capsules and allow transplant within vascularized tissue spaces, thereby reducing islet mass requirements and graft volumes. By delivering poly(ethylene glycol)-encapsulated islets to an isolated, retrievable, and highly vascularized site via a vasculogenic delivery vehicle, we demonstrate that a single pancreatic donor syngeneic islet mass exhibits improved long-term function over conventional alginate capsules and close integration with transplant site vasculature. In vivo tracking of bioluminescent allogeneic encapsulated islets in an autoimmune type 1 diabetes murine model showed enhanced cell survival over unencapsulated islets in the absence of chronic systemic immunosuppression. This method demonstrates a translatable alternative to intraperitoneal encapsulated islet transplant.


Assuntos
Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/terapia , Insulina/metabolismo , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/citologia , Microfluídica/métodos , Polietilenoglicóis/química , Animais , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 1/patologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
20.
Nat Mater ; 17(8): 732-739, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29867165

RESUMO

Islet transplantation is a promising therapy for type 1 diabetes. However, chronic immunosuppression to control rejection of allogeneic islets induces morbidities and impairs islet function. T effector cells are responsible for islet allograft rejection and express Fas death receptors following activation, becoming sensitive to Fas-mediated apoptosis. Here, we report that localized immunomodulation using microgels presenting an apoptotic form of the Fas ligand with streptavidin (SA-FasL) results in prolonged survival of allogeneic islet grafts in diabetic mice. A short course of rapamycin treatment boosted the immunomodulatory efficacy of SA-FasL microgels, resulting in acceptance and function of allografts over 200 days. Survivors generated normal systemic responses to donor antigens, implying immune privilege of the graft, and had increased CD4+CD25+FoxP3+ T regulatory cells in the graft and draining lymph nodes. Deletion of T regulatory cells resulted in acute rejection of established islet allografts. This localized immunomodulatory biomaterial-enabled approach may provide an alternative to chronic immunosuppression for clinical islet transplantation.


Assuntos
Materiais Biocompatíveis/metabolismo , Materiais Biocompatíveis/farmacologia , Proteína Ligante Fas/metabolismo , Proteína Ligante Fas/farmacologia , Imunomodulação/efeitos dos fármacos , Transplante das Ilhotas Pancreáticas/imunologia , Animais , Camundongos , Estreptavidina/metabolismo , Transplante Homólogo
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