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1.
Int J Biol Macromol ; 275(Pt 1): 133586, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38960242

RESUMEN

In the face of agricultural challenges posed by both abiotic and biotic stressors, phytopathogens emerge as formidable threats to crop productivity. Conventional methods, involving the use of pesticides and microbes, often lead to unintended consequences. In addressing this issue, ICAR -Indian Institute of Oilseeds Research (ICAR-IIOR) has developed a chitosan-based double-layer seed coating. Emphasizing crop input compatibility, entrapment, and characterization, the study has yielded promising results. The double-layer coating on groundnut seeds enhanced germination and seedling vigor. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the structural changes and entrapment of crop inputs. The persistence of T. harzianum (Th4d) and Bradyrhizobium sp. in chitosan blended film in studied soils revealed that viable propogules of Th4d were recorded in double layer treatment combination with 3.54 and 3.50 Log CFUs/g of soil (colony forming units) and Bradyrhizobium sp. with 5.34 and 5.27 Log CFUs/g of soil at 90 days after application (DAA). Root colonization efficacy studies of Th4d and Bradyrhizobium sp. in groundnut crop in studied soils revealed that, maximum viable colonies were observed at 45 days after sowing (DAS). This comprehensive study highlights the potential of chitosan-based double-layer seed coating providing a promising and sustainable strategy for stress management in agriculture.


Asunto(s)
Bradyrhizobium , Quitosano , Semillas , Estrés Fisiológico , Quitosano/química , Quitosano/farmacología , Semillas/efectos de los fármacos , Bradyrhizobium/efectos de los fármacos , Bradyrhizobium/fisiología , Estrés Fisiológico/efectos de los fármacos , Germinación/efectos de los fármacos , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Vigna/efectos de los fármacos , Vigna/crecimiento & desarrollo
2.
PLoS One ; 19(7): e0305744, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39074090

RESUMEN

Using a cutting-edge net-shape manufacturing technique called Additive Layer Manufacturing (ALM), highly complex components that are not achievable with conventional wrought and cast methods can be produced. As a result, the aerospace sector is paying closer attention to using this technology to fabricate superalloys based on nickel to develop the holistic gas turbine. Because of this, there is an increasing need for the mechanical characterisation of such material. Conventional mechanical testing is hampered by the limited availability of material that has been processed, especially given the large number of process factors that need to be assessed. Thus, the present study focuses on manufacturing CM247LC Ni-based superalloy with exceptional mechanical characteristics by laser powder bed fusion (L-PBF). This study evaluates the effect of input process variables such as laser power, scan speed, hatch distance and volumetric energy density on the mechanical performance of the LPBF CM247LC superalloy. The maximum value of as-built tensile strength obtained in the study is 997.81 MPa. Plotting Pearson's heatmap and the Feature importance (F-test) was used in the data analysis to examine the impact of input parameters on tensile strength. The accuracy of the tensile strength data classification by machine learning algorithms, such as k-nearest neighbours, Naïve Baiyes, Support vector machine, XGBoost, AdaBoost, Decision tree, Random forest, and logistic regression algorithms, was 92.5%, 83.75%, 83%, 85%, 87.5%, 90%, 91.25%, and 77.5%, respectively.


Asunto(s)
Aleaciones , Aprendizaje Automático , Resistencia a la Tracción , Aleaciones/química , Ensayo de Materiales/métodos , Níquel/química , Algoritmos
3.
Sci Rep ; 14(1): 9683, 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38678121

RESUMEN

Surface integrity is one of the key elements used to judge the quality of machined surfaces, and surface roughness is one such quality parameter that determines the pass level of the machined product. In the present study, AISI D2 steel was machined with electric discharge at different process parameters using Jatropha and EDM oil. Titanium dioxide (TiO2) nanopowder was added to the dielectric to improve surface integrity. Experiments were performed using the one variable at a time (OVAT) approach for EDM oil and Jatropha oil as dielectric media. From the experimental results, it was observed that response trends of surface roughness (SR) using Jatropha oil are similar to those of commercially available EDM oil, which proves that Jatropha oil is a technically and operationally feasible dielectric and can be efficiently replaced as dielectric fluid in the EDM process. The lowest value of S.R. (i.e., 4.5 microns) for EDM and Jatropha oil was achieved at current = 9 A, Ton = 30 µs, Toff = 12 µs, and Gap voltage = 50 V. As the values of current and pulse on time increase, the S.R. also increases. Current and pulse-on-time were the most significant parameters affecting S.R. Machine learning methods like linear regression, decision trees, and random forests were used to predict the surface roughness. Random forest modeling is highly accurate, with an R2 value of 0.89 and an MSE of 1.36% among all methods. Random forest models have better predictive capabilities and may be one of the best options for modeling complex EDM processes.

4.
ACS Biomater Sci Eng ; 10(4): 2212-2223, 2024 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-38467019

RESUMEN

Macrophages are innate immune cells that interact with complex extracellular matrix environments, which have varied stiffness, composition, and structure, and such interactions can lead to the modulation of cellular activity. Collagen is often used in the culture of immune cells, but the effects of substrate functionalization conditions are not typically considered. Here, we show that the solvent system used to attach collagen onto a hydrogel surface affects its surface distribution and organization, and this can modulate the responses of macrophages subsequently cultured on these surfaces in terms of their inflammatory activation and expression of adhesion and mechanosensitive molecules. Collagen was solubilized in either acetic acid (Col-AA) or N-(2-hydroxyethyl)piperazine-N'-ethanesulfonic acid (HEPES) (Col-HEP) solutions and conjugated onto soft and stiff polyacrylamide (PA) hydrogel surfaces. Bone marrow-derived macrophages cultured under standard conditions (pH 7.4) on the Col-HEP-derived surfaces exhibited stiffness-dependent inflammatory activation; in contrast, the macrophages cultured on Col-AA-derived surfaces expressed high levels of inflammatory cytokines and genes, irrespective of the hydrogel stiffness. Among the collagen receptors that were examined, leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) was the most highly expressed, and knockdown of the Lair-1 gene enhanced the secretion of inflammatory cytokines. We found that the collagen distribution was more homogeneous on Col-AA surfaces but formed aggregates on Col-HEP surfaces. The macrophages cultured on Col-AA PA hydrogels were more evenly spread, expressed higher levels of vinculin, and exerted higher traction forces compared to those of cells on Col-HEP. These macrophages on Col-AA also had higher nuclear-to-cytoplasmic ratios of yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), key molecules that control inflammation and sense substrate stiffness. Our results highlight that seemingly slight variations in substrate deposition for immunobiology studies can alter critical immune responses, and this is important to elucidate in the broader context of immunomodulatory biomaterial design.


Asunto(s)
Colágeno , Matriz Extracelular , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Macrófagos/metabolismo , Factores de Transcripción/metabolismo , Hidrogeles/metabolismo , Citocinas/metabolismo
5.
Sci Signal ; 16(783): eadc9656, 2023 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-37130167

RESUMEN

Innate immune cells are responsible for eliminating foreign infectious agents and cellular debris, and their ability to perceive, respond to, and integrate biochemical and mechanical cues from their microenvironment eventually determines their behavior. In response to tissue injury, pathogen invasion, or a biomaterial implant, immune cells activate many pathways to initiate inflammation in the tissue. In addition to common inflammatory pathways, studies have demonstrated the role of the mechanosensitive proteins and transcriptional coactivators YAP and TAZ (YAP/TAZ) in inflammation and immunity. We review our knowledge of YAP/TAZ in controlling inflammation and immunity in innate immune cells. Furthermore, we discuss the roles of YAP/TAZ in inflammatory diseases, wound healing, and tissue regeneration and how they integrate mechanical cues with biochemical signaling during disease progression. Last, we comment on possible approaches that can be exploited to harness the therapeutic potential of YAP/TAZ in inflammatory diseases.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Transducción de Señal , Humanos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Inflamación , Inmunidad Innata
6.
Biomater Sci ; 11(2): 596-610, 2023 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-36476811

RESUMEN

Cancer vaccine immunotherapy facilitates the immune system's recognition of tumor-associated antigens, and the biomolecular design of these vaccines using nanoparticles is one important approach towards obtaining strong anti-tumor responses. Following activation of dendritic cells (DCs), a robust CD8+ T cell-mediated adaptive immune response is critical for tumor elimination. While the role of efficient antigen-presenting myeloid DCs (mDCs) is conventionally attributed towards vaccine efficacy, participation by highly cytokine-producing plasmacytoid DCs (pDCs) is less understood and is often overlooked. We examined vaccines based on the E2 protein nanoparticle platform that delivered encapsulated TLR9 agonist bacterial-like DNA (CpG1826 or CpG1018) or TLR7 agonist viral ssRNA to determine their efficacy over free agonists in activating both mDCs and pDCs for antigen presentation. Although mDCs were only activated by nanoparticle-encapsulated TLR9 agonists, pDCs were activated by all the individually tested constructs, and CpG1826 was shown to induce pDC cytokine production. Transfer of secreted factors from pDCs that were stimulated with a vaccine formulation comprising peptide antigen and CpG1826 enhanced mDC display of the antigen, particularly when delivered in nanoparticles. Only when treated with nanoparticle-conjugated vaccine could pDCs secrete factors to induce antigen display on naïve mDCs. These results reveal that pDCs can aid mDCs, highlighting the importance of activating both pDCs and mDCs in designing effective cancer vaccines, and demonstrate the advantage of using nanoparticle-based vaccine delivery.


Asunto(s)
Neoplasias , Vacunas , Humanos , Receptor Toll-Like 9/metabolismo , Citocinas/metabolismo , Linfocitos T CD8-positivos , Neoplasias/metabolismo , Células Dendríticas
7.
Mater Today Bio ; 17: 100455, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36304975

RESUMEN

Bioluminescence imaging has advantages over fluorescence imaging, such as minimal photobleaching and autofluorescence, and greater signal-to-noise ratios in many complex environments. Although significant achievements have been made in luciferase engineering for generating bright and stable reporters, the full capability of luciferases for nanoparticle tracking has not been comprehensively examined. In biocatalysis, enhanced enzyme performance after immobilization on nanoparticles has been reported. Thus, we hypothesized that by assembling luciferases onto a nanoparticle, the resulting complex could lead to substantially improved imaging properties. Using a modular bioconjugation strategy, we attached NanoLuc (NLuc) or Akaluc bioluminescent proteins to a protein nanoparticle platform (E2), yielding nanoparticles NLuc-E2 and Akaluc-E2, both with diameters of ∼45 â€‹nm. Although no significant differences were observed between different conditions involving Akaluc and Akaluc-E2, free NLuc at pH 5.0 showed significantly lower emission values than free NLuc at pH 7.4. Interestingly, NLuc immobilization on E2 nanoparticles (NLuc-E2) emitted increased luminescence at pH 7.4, and at pH 5.0 showed over two orders of magnitude (>200-fold) higher luminescence (than free NLuc), expanding the potential for imaging detection using the nanoparticle even upon endocytic uptake. After uptake by macrophages, the resulting luminescence with NLuc-E2 nanoparticles was up to 7-fold higher than with free NLuc at 48 â€‹h. Cells incubated with NLuc-E2 could also be imaged using live bioluminescence microscopy. Finally, biodistribution of nanoparticles into lymph nodes was detected through imaging using NLuc-E2, but not with conventionally-labeled fluorescent E2. Our data demonstrate that NLuc-bound nanoparticles have advantageous properties that can be utilized in applications ranging from single-cell imaging to in vivo biodistribution.

8.
Pediatr Pulmonol ; 57(10): 2383-2389, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35759423

RESUMEN

BACKGROUND AND OBJECTIVE: With improved survival in neonates with meconium aspiration syndrome (MAS), the focus is currently on mitigating the morbidities. The objective of this study was to predict factors determining prolonged hospital stay in neonates with MAS. MATERIALS AND METHODS: It was a retrospective cohort from five centers of south India between 2018 and 2020. Neonates ≥35 weeks of gestation admitted to neonatal intensive care unit with the diagnosis of MAS and requiring oxygen beyond 24 h of life were included in the study. The morbidities in the neonates with stay ≤7 days (short stay) were compared with >7 days (prolonged stay). Logistic regression by the backward stepwise method was used for predictive score creation. RESULTS: Out of 347 neonates with MAS discharged home, 103 (29%) had a short stay and 244 (71%) had prolonged stay. The primary support beyond O2 (continuous positive airway pressure/mechanical ventilation) (42% vs. 83%, p < 0.001), fractional inspired oxygen (FiO2 ) at 1 h >30% (45% vs. 87%, p < 0.001), hypoxic ischemic encephalopathy (HIE) stage 2 or 3 (1% vs. 27%, p < 0.001), moderate-severe persistent pulmonary artery hypertension (PPHN) (3% vs. 31%, p < 0.001) were independent factors associated with prolonged stay on logistic regression. A prediction model was devised using weighted scores of these four associated morbidities. The clinical score thus developed had 83% sensitivity, 68% specificity for the prediction of prolonged stay (area under curve: 82%, 95% confidence interval [78-87], p < 0.001). CONCLUSION: More than two-thirds of neonates with MAS had prolonged stay. The primary support beyond oxygen, FiO2 requirement >30%, Moderate to severe PPHN, HIE stage 2 or 3 were predictive of prolonged stay in neonates with MAS.


Asunto(s)
Hipertensión Pulmonar , Síndrome de Aspiración de Meconio , Femenino , Humanos , Hipertensión Pulmonar/complicaciones , Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Tiempo de Internación , Síndrome de Aspiración de Meconio/complicaciones , Síndrome de Aspiración de Meconio/terapia , Oxígeno , Estudios Retrospectivos
9.
RSC Adv ; 12(13): 7742-7756, 2022 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-35424752

RESUMEN

In the tumor micro-environment, tumor associated macrophages (TAMs) represent a predominant component of the total tumor mass, and TAMs play a complex and diverse role in cancer pathogenesis with potential for either tumor suppressive, or tumor promoting biology. Thus, understanding macrophage localization and function are essential for cancer diagnosis and treatment. Typically, tissue biopsy is used to evaluate the density and polarization of TAMs, but provides a limited "snapshot" in time of a dynamic and potentially heterogeneous tumor immune microenvironment. Imaging has the potential for three-dimensional mapping; however, there is a paucity of macrophage-targeted contrast agents to specifically detect TAM subtypes. We have previously found that sulfated-dextran coated iron oxide nanoparticles (SDIO) can target macrophage scavenger receptor A (SR-A, also known as CD204). Since CD204 (SR-A) is considered a biomarker for the M2 macrophage polarization, these SDIO might provide M2-specific imaging probes for MRI. In this work, we investigate whether SDIO can label M2-polarized cells in vitro. We evaluate the effect of degree of sulfation on uptake by primary cultured bone marrow derived macrophages (BMDM) and found that a higher degree of sulfation led to higher uptake, but there were no differences across the subtypes. Further analysis of the BMDM showed similar SR-A expression across stimulation conditions, suggesting that this classic model for macrophage subtypes may not be ideal for definitive M2 subtype marker expression, especially SR-A. We further examine the localization of SDIO in TAMs in vivo, in the mammary fat pad mouse model of breast cancer. We demonstrate that uptake by TAMs expressing SR-A scales with degree of sulfation, consistent with the in vitro studies. The TAMs demonstrate M2-like function and secrete Arg-1 but not iNOS. Uptake by these M2-like TAMs is validated by immunohistochemistry. SDIO show promise as a valuable addition to the toolkit of imaging probes targeted to different biomarkers for TAMs.

11.
Anaesth Rep ; 10(1): e12154, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35360363

RESUMEN

Hypermagnesaemia is an uncommon electrolyte disorder which can be fatal if not recognised and treated promptly. The signs and symptoms of hypermagnesaemia are non-specific, making it an under-diagnosed cause of cardiovascular dysfunction, hypocalcaemia, and neurological and respiratory depression. Since magnesium homeostasis is handled almost exclusively by the kidneys, symptomatic hypermagnesaemia seldom occurs in the context of normal renal function; when it does, it is usually iatrogenic. Here, we report a case of iatrogenic hypermagnesaemia which presented as respiratory depression, preventing weaning from mechanical ventilation following cardiac surgery in a patient in the early stages of chronic kidney disease. On investigation he was found to have isolated severe hypermagnesaemia, following an intravenous bolus of magnesium sulphate administered intra-operatively to treat tachyarrhythmia. Before administering intravenous magnesium therapeutically, it is important for clinicians to assess renal function and baseline serum magnesium along with other possible risk factors for hypermagnesaemia, and to actively look for signs and symptoms of magnesium toxicity when the patient is receiving therapeutic magnesium.

12.
Cartilage ; 13(1): 19476035221081466, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35313741

RESUMEN

OBJECTIVE: Tissue-engineered cartilage implants must withstand the potential inflammatory and joint loading environment for successful long-term repair of defects. The work's objectives were to develop a novel, direct cartilage-macrophage co-culture system and to characterize interactions between self-assembled neocartilage and differentially stimulated macrophages. DESIGN: In study 1, it was hypothesized that the proinflammatory response of macrophages would intensify with increasing construct stiffness; it was expected that the neocartilage would display a decrease in mechanical properties after co-culture. In study 2, it was hypothesized that bioactive factors would protect neocartilage properties during macrophage co-culture. Also, it was hypothesized that interleukin 10 (IL-10)-stimulated macrophages would improve neocartilage mechanical properties compared to lipopolysaccharide (LPS)-stimulated macrophages. RESULTS: As hypothesized, stiffer neocartilage elicited a heightened proinflammatory macrophage response, increasing tumor necrosis factor alpha (TNF-α) secretion by 5.47 times when LPS-stimulated compared to construct-only controls. Interestingly, this response did not adversely affect construct properties for the stiffest neocartilage but did correspond to a significant decrease in aggregate modulus for soft and medium stiffness constructs. In addition, bioactive factor-treated constructs were protected from macrophage challenge compared to chondrogenic medium-treated constructs, but IL-10 did not improve neocartilage properties, although stiff constructs appeared to bolster the anti-inflammatory nature of IL-10-stimulated macrophages. However, co-culture of bioactive factor-treated constructs with LPS-treated macrophages reduced TNF-α secretion by over 4 times compared to macrophage-only controls. CONCLUSIONS: In conclusion, neocartilage stiffness can mediate macrophage behavior, but stiffness and bioactive factors prevent macrophage-induced degradation. Ultimately, this co-culture system could be utilized for additional studies to develop the burgeoning field of cartilage mechano-immunology.


Asunto(s)
Cartílago Articular , Condrocitos , Cartílago Articular/fisiología , Condrocitos/metabolismo , Técnicas de Cocultivo , Interleucina-10/metabolismo , Lipopolisacáridos/metabolismo , Lipopolisacáridos/farmacología , Macrófagos , Factor de Necrosis Tumoral alfa
13.
ACS Nano ; 16(2): 3311-3322, 2022 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-35080856

RESUMEN

Natural load-bearing mammalian tissues, such as cartilage and ligaments, contain ∼70% water yet can be mechanically stiff and strong due to the highly templated structures within. Here, we present a bioinspired approach to significantly stiffen and strengthen biopolymer hydrogels and films through the combination of nanoscale architecture and templated microstructure. Imprinted submicrometer pillar arrays absorb energy and deflect cracks. The produced chitosan hydrogels show nanofiber chains aligned by nanopillar topography, subsequently templating the microstructure throughout the film. These templated nanopillar chitosan hydrogels mechanically outperform unstructured flat hydrogels, with increases in the moduli of ∼160%, up to ∼20 MPa, and work at break of ∼450%, up to 8.5 MJ m-3. Furthermore, the strength at break increases by ∼350%, up to ∼37 MPa, and it is one of the strongest hydrogels yet reported. The nanopillar templating strategy is generalizable to other biopolymers capable of forming oriented domains and strong interactions. Overall, this process yields hydrogel films that demonstrate mechanical performance comparable to that of other stiff, strong hydrogels and natural tissues.


Asunto(s)
Quitosano , Nanofibras , Animales , Biopolímeros/química , Cartílago , Quitosano/química , Hidrogeles/química , Nanofibras/química
14.
Indian Heart J ; 73(6): 737-739, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34861984

RESUMEN

This observational study investigates the prognostic significance of troponin I in patients undergoing primary percutaneous intervention (pPCI). Sequential cardiac biomarker sampling of the enrolled patients (n = 167) was performed on admission and at 6,12,24 and 48 h. Clinical characteristics, major adverse cardiac and cerebrovascular events (MACCE) (death, reinfarction, stroke and new or worsening heart failure) and left ventricular ejection fraction (LVEF) were noted on admission and 30 day follow-up. A 24-h troponin I level >60 ng/ml predicted MACCE (OR 4.06, p = 0.023; adjusted OR 5.09, p = 0.034) and less than 10% improvement in LVEF on follow-up (OR 2.49, p = 0.007). Thus, in patients undergoing pPCI, 24-h cardiac Troponin I is a good non-invasive surrogate to predict MACCE and improvement in LVEF.


Asunto(s)
Intervención Coronaria Percutánea , Troponina I , Humanos , Pronóstico , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular Izquierda
15.
Biomaterials ; 279: 121236, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34753038

RESUMEN

Macrophages are mechanosensitive cells that can exquisitely fine-tune their function in response to their microenvironment. While macrophage polarization results in concomitant changes in cell morphology and epigenetic reprogramming, how biophysically-induced signaling cascades contribute to gene regulatory programs that drive polarization remains unknown. We reveal a cytoskeleton-dependent Src-H3 acetylation (H3Ac) axis responsible for inflammation-associated histone hyperacetylation. Inflammatory stimuli caused increases in traction forces, Src activity and H3Ac marks in macrophages, accompanied by reduced cell elongation and motility. These effects were curtailed following disruption of H3Ac-signaling through either micropattern-induced cell elongation or inhibition of H3Ac readers (BRD proteins) directly. Src activation relieves the suppression of p300 histone acetyltransferase (HAT) activity by PKCδ. Furthermore, while inhibition of Src reduced p300 HAT activity and H3Ac marks globally, local H3Ac levels within the Src promoter were increased, suggesting H3Ac regulates Src levels through feedback. Together, our study reveals an adhesome-to-epigenome regulatory nexus underlying macrophage mechanosensation, where Src modulates H3Ac-associated epigenetic signaling as a means of tuning inflammatory gene activity and macrophage fate decisions in response to microenvironmental cues.


Asunto(s)
Histona Acetiltransferasas , Histonas , Acetilación , Histona Acetiltransferasas/metabolismo , Histonas/metabolismo , Macrófagos/metabolismo , Transducción de Señal
16.
Front Immunol ; 12: 689397, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34630381

RESUMEN

Macrophages are versatile cells of the innate immune system that perform diverse functions by responding to dynamic changes in their microenvironment. While the effects of soluble cues, including cytokines and chemokines, have been widely studied, the effects of physical cues, including mechanical stimuli, in regulating macrophage form and function are less well understood. In this study, we examined the effects of static and cyclic uniaxial stretch on macrophage inflammatory and healing activation. We found that cyclic stretch altered macrophage morphology and responses to IFNγ/LPS and IL4/IL13. Interestingly, we found that both static and cyclic stretch suppressed IFNγ/LPS induced inflammation. In contrast, IL4/IL13 mediated healing responses were suppressed with cyclic but enhanced with static stretch conditions. Mechanistically, both static and cyclic stretch increased expression of the integrin CD11b (αM integrin), decreased expression of the mechanosensitive ion channel Piezo1, and knock down of either CD11b or Piezo1 through siRNA abrogated stretch-mediated changes in inflammatory responses. Moreover, we found that knock down of CD11b enhanced the expression of Piezo1, and conversely knock down of Piezo1 enhanced CD11b expression, suggesting the potential for crosstalk between integrins and ion channels. Finally, stretch-mediated differences in macrophage activation were also dependent on actin, since pharmacological inhibition of actin polymerization abrogated the changes in activation with stretch. Together, this study demonstrates that the physical environment synergizes with biochemical cues to regulate macrophage morphology and function, and suggests a role for CD11b and Piezo1 crosstalk in mechanotransduction in macrophages.


Asunto(s)
Antígeno CD11b/inmunología , Canales Iónicos/inmunología , Macrófagos/inmunología , Mecanotransducción Celular , Animales , Supervivencia Celular , Células Cultivadas , Femenino , Activación de Macrófagos , Ratones Endogámicos C57BL , Ratones Transgénicos
17.
Biomater Sci ; 9(23): 7851-7861, 2021 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-34514479

RESUMEN

Evaluating the host immune response to biomaterials is an essential step in the development of medical devices and tissue engineering strategies. To aid in this process, in vitro studies, whereby immune cells such as macrophages are cultured on biomaterials, can often expedite high throughput testing of many materials prior to implantation. While most studies to date utilize murine or human cells, the use of porcine macrophages has been less well described, despite the prevalent use of porcine models in medical device and tissue engineering development. In this study, we describe the isolation and characterization of porcine bone marrow- and peripheral blood-derived macrophages, and their interactions with biomaterials. We confirmed the expression of the macrophage surface markers CD68 and F4/80 and characterized the porcine macrophage response to the inflammatory stimulus, bacterial lipopolysaccharide. Finally, we investigated the inflammatory and fusion response of porcine macrophages cultured on different stiffness hydrogels, and we found that stiffer hydrogels enhanced inflammatory activation by more than two-fold and promoted fusion to form foreign body giant cells. Together, this study establishes the use of porcine macrophages in biomaterial testing and reveals a stiffness-dependent effect on biomaterial-induced giant cell formation.


Asunto(s)
Materiales Biocompatibles , Macrófagos , Porcinos , Animales , Hidrogeles , Ensayo de Materiales , Ingeniería de Tejidos
18.
Nat Commun ; 12(1): 3256, 2021 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-34059671

RESUMEN

Macrophages perform diverse functions within tissues during immune responses to pathogens and injury, but molecular mechanisms by which physical properties of the tissue regulate macrophage behavior are less well understood. Here, we examine the role of the mechanically activated cation channel Piezo1 in macrophage polarization and sensing of microenvironmental stiffness. We show that macrophages lacking Piezo1 exhibit reduced inflammation and enhanced wound healing responses. Additionally, macrophages expressing the transgenic Ca2+ reporter, Salsa6f, reveal that Ca2+ influx is dependent on Piezo1, modulated by soluble signals, and enhanced on stiff substrates. Furthermore, stiffness-dependent changes in macrophage function, both in vitro and in response to subcutaneous implantation of biomaterials in vivo, require Piezo1. Finally, we show that positive feedback between Piezo1 and actin drives macrophage activation. Together, our studies reveal that Piezo1 is a mechanosensor of stiffness in macrophages, and that its activity modulates polarization responses.


Asunto(s)
Materiales Biocompatibles/efectos adversos , Reacción a Cuerpo Extraño/inmunología , Canales Iónicos/metabolismo , Macrófagos/inmunología , Cicatrización de Heridas/inmunología , Actinas/metabolismo , Animales , Células Cultivadas , Microambiente Celular/inmunología , Modelos Animales de Enfermedad , Retroalimentación Fisiológica , Femenino , Humanos , Canales Iónicos/genética , Activación de Macrófagos , Macrófagos/metabolismo , Masculino , Mecanotransducción Celular/inmunología , Ratones , Cultivo Primario de Células , Tejido Subcutáneo/cirugía
19.
ACS Sustain Chem Eng ; 9(14): 4957-4966, 2021 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-33868834

RESUMEN

MAX phases are layered ternary carbides or nitrides that are attractive for catalysis applications due to their unusual set of properties. They show high thermal stability like ceramics, but they are also tough, ductile, and good conductors of heat and electricity like metals. Here, we study the potential of the Ti3AlC2 MAX phase as a support for molybdenum oxide for the reverse water-gas shift (RWGS) reaction, comparing this new catalyst to more traditional materials. The catalyst showed higher turnover frequency values than MoO3/TiO2 and MoO3/Al2O3 catalysts, due to the outstanding electronic properties of the Ti3AlC2 support. We observed a charge transfer effect from the electronically rich Ti3AlC2 MAX phase to the catalyst surface, which in turn enhances the reducibility of MoO3 species during reaction. The redox properties of the MoO3/Ti3AlC2 catalyst improve its RWGS intrinsic activity compared to TiO2- and Al2O3-based catalysts.

20.
Membranes (Basel) ; 11(2)2021 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-33557066

RESUMEN

Tetraethylorthosilicate (TEOS)-crosslinked poly(vinyl alcohol) (PVA) solution was prepared and treated with benzaldehyde 2 sulphonic sodium salt acid (B2SA) for sulfonation. Different contents of graphene were incorporated into B2SA-grafted PVA-TEOS hybrid membrane to improve the membrane stability, mechanical strength, and overall pervaporation performance of the membranes. Membranes were fabricated using the casting technique. Developed membranes were then analyzed for their physicochemical changes by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscope (SEM), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), contact angle analysis (CA), and mechanical strength. The lower d-spacing value observed in WAXD was evidence for the decreased inter-chain distance between the polymer chains. DSC exhibited the enhanced thermal stability of the developed membranes compared to the plane PVA membrane with enhancement in Tg value (106 °C), which was well above the pervaporation experimental temperature. Incorporation of graphene induced higher mechanical strength to the fabricated membranes. Further, the membranes were tested for the pervaporation separation of bioethanol. All the membranes were stable throughout the pervaporation studies, with M-2 G showing the total permeation flux of 11.66 × 10-2 kg/(m2 h) at 30 °C.

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