1,721,236 research outputs found
Therapies to prevent post-infarction remodelling: From repair to regeneration
Full text linkMyocardial infarction is the first cause of worldwide mortality, with an increasing incidence also reported in developing countries. Over the past decades, preclinical research and clinical trials continually tested the efficacy of cellular and acellular-based treatments. However, none of them resulted in a drug or device currently used in combination with either percutaneous coronary intervention or coronary artery bypass graft. Inflammatory, proliferation and remodelling phases follow the ischaemic event in the myocardial tissue. Only recently, singlecell sequencing analyses provided insights into the specific cell populations which determine the final fibrotic deposition in the affected region. In this review, ischaemia, inflammation, fibrosis, angiogenesis, cellular stress and fundamental cellular and molecular components are evaluated as therapeutic targets. Given the emerging evidence of biomaterial-based systems, the increasing use of injectable hydrogels/scaffolds and epicardial patches is reported both as acellular and cellularised/functionalised treatments. Since several variables influence the outcome of any experimented treatment, we return to the pathological basis with an unbiased view towards any specific process or cellular component. Thus, by evaluating the benefits and limitations of the approaches based on these targets, the reader can weigh the rationale of each of the strategies that reached the clinical trials stage. As recent studies focused on the relevance of the extracellular matrix in modulating ischaemic remodelling and enhancing myocardial regeneration, we aim to portray current trends in the field with this review. Finally, approaches towards feasible translational studies that are as yet unexplored are also suggested
Targeted Approaches to Inhibit Sialylation of Multiple Myeloma in the Bone Marrow Microenvironment
No full textAberrant glycosylation modulates different aspects of tumor biology, and it has long been recognized as a hallmark of cancer. Among the different forms of glycosylation, sialylation, the addition of sialic acid to underlying oligosaccharides, is often dysregulated in cancer. Increased expression of sialylated glycans has been observed in many types of cancer, including multiple myeloma, and often correlates with aggressive metastatic behavior. Myeloma, a cancer of plasma cells, develops in the bone marrow, and colonizes multiple sites of the skeleton including the skull. In myeloma, the bone marrow represents an essential niche where the malignant cells are nurtured by the microenvironment and protected from chemotherapy. Here, we discuss the role of hypersialylation in the metastatic process focusing on multiple myeloma. In particular, we examine how increased sialylation modulates homing of malignant plasma cells into the bone marrow by regulating the activity of molecules important in bone marrow cellular trafficking including selectins and integrins. We also propose that inhibiting sialylation may represent a new therapeutic strategy to overcome bone marrow-mediated chemotherapy resistance and describe different targeted approaches to specifically deliver sialylation inhibitors to the bone marrow microenvironment
Synthetic/ECM-inspired hybrid platform for hollow microcarriers with ROS-triggered nanoporation hallmarks
Full text linkReactive oxygen species (ROS) are key pathological signals expressed in inflammatory diseases such as cancer, ischemic conditions and atherosclerosis. An ideal drug delivery system should not only be responsive to these signals but also should not elicit an unfavourable host response. This study presents an innovative platform for drug delivery where a natural/synthetic composite system composed of collagen type I and a synthesized polythioether, ensures a dual stimuli-responsive behaviour. Collagen type I is an extracellular matrix constituent protein, responsive to matrix metalloproteinases (MMP) cleavage per se. Polythioethers are stable synthetic polymers characterized by the presence of sulphur, which undergoes a ROS-responsive swelling switch. A polythioether was synthesised, functionalized and tested for cytotoxicity. Optimal conditions to fabricate a composite natural/synthetic hollow sphere construct were optimised by a template-based method. Collagen-polythioether hollow spheres were fabricated, revealing uniform size and ROS-triggered nanoporation features. Cellular metabolic activity of H9C2 cardiomyoblasts remained unaffected upon exposure to the spheres. Our natural/synthetic hollow microspheres exhibit the potential for use as a pathological stimuli-responsive reservoir system for applications in inflammatory diseases.This material is based upon works supported by the European Union funding under the AngioMatTrain 7th Framework Programme, Grant Agreement Number 317304. This publication has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) and is co-funded under the European Regional Development Fund under Grant Number 13/RC/2073. The authors acknowledge the use of the facilities and the scientific and technical assistance of the Centre for Microscopy and Imaging at the National University of Ireland Galway (www.imagingnuigalway.ie), a facility that is co-funded by the Irish Government’s Programme for Research in Third Level Institutions, Cycles 4 and 5, National Development Plan 2007–2013
An optimized protocol for combined fluorescent lectin/immunohistochemistry to characterize tissue-specific glycan distribution in human or rodent tissues
Full text link: Lectin histochemical analysis of tissues combined with immunohistochemistry is a valuable tool to characterize and correlate the spatial distribution of glycans with the presence of specific cell types or antigens of interest. The current protocol describes the application of monosaccharide motif specificity of lectin binding to glycan residues to different tissue types. In addition, we describe stereological methods to provide further quantification of the analyzed tissues. For complete details on the use and execution of this protocol, please refer to Mohd Isa et al. (2018), Contessotto et al. (2020), and Samal et al. (2020)
Synthesis of model compounds acting as Nitric Oxide (NO)-scavengers and the fabrication of NO-scavenging hydrogels targeting the treatment of triple-negative breast cancer
No full textTriple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer, with an early recurrence within two to three years of first diagnosis. Moreover, the heterogeneity of the TNBC tissue creates difficulty in developing specific treatments for different TNBC subtypes. At certain stages of its development, a correlation exists between the tumour progression of TNBC and the overexpression of inducible nitric oxide synthase (iNOS). Hence, the modulation of the intracellular levels of ●NO can be employed to treat this type of tumour by inhibiting the metastatic behaviour of cancer cells and decreasing angiogenesis. Various NOS inhibitors can slow down the migration of TNBC cells. However, these inhibitors have certain drawbacks, such as a lack of specificity and reduced commercial interest in developing related therapeutics. To overcome these limitations, ●NO-scavenging is proposed as an alternative approach to reduce the intracellular levels of ●NO and inhibit cancer cell migration. The goal of this thesis is to target TNBC cell migration and angiogenesis within the tumour tissue through ●NO-scavenging. The goal was to synthesize several hemin-based ●NO-scavenging compounds and develop functional hyaluronic acid (HA)- based ●NO-scavenging hydrogels. The biological effects of these compounds were evaluated in vitro and in vivo. The initial stage of the project involved examining the effectiveness of hemin as a model compound for ●NO-scavenging and its impact on TNBC cell migration, the production of reactive oxygen species, and the expression of glycoproteins associated with metastasis. Additionally, the study examined the expression of epithelial-mesenchymal transition markers and mitochondrial functions in TNBC cells. Next, considering the catalytic processes of hemin for nitrite/H2O2-induced protein nitration, its influence in combination with ●NO on the nitration of cellular proteins was also evaluated. Furthermore, the mechanism of hemin/●NO-catalyzed nitration of BSA as a model protein was studied. This was a mechanistic study for the initial evaluation of the cellular effects of hemin and ●NO, and the influence of ●NO-scavenging in a group of molecular events in the TNBC cells. Modification of the properties of hemin through conjugation to specific aromatic moieties was the next step. The objective of this step was to reduce the aggregation behaviour of hemin molecules, protect them against oxidative degradation, and preserve their ●NO-scavenging efficiency. The properties of hemin and its derivatives were evaluated experimentally and theoretically. Next, their cytocompatibility was evaluated by measuring their effects on the intracellular levels of ●NO in TNBC cells, migration, and the accompanying downstream effects. Furthermore, the effects of different compounds on the ●NOinduced vasodilation in zebrafish embryos were investigated. The study introduced a novel class of iron based ●NO-scavenging compounds, which were synthesized using straightforward procedures and possessed unique chemical properties. Furthermore, the synthesized compounds exhibited diverse abilities to regulate TNBC cell migration and blood vessel dilation, each with distinct molecular effects at the cellular level. Next, the study investigated the interactions between HA, one of the primary components of the hydrogels, and ●NO, as well as how these interactions can lead to HA fragmentation. These interactions inhibited TNBC cell migration and dilation of blood vessels in zebrafish embryos. While ●NO induced the depolymerization of HA chains, with similar effects to other active radicals, hemin and its different derivatives prevented that with different levels. These interactions were examined via several techniques to understand how HA can scavenge ●NO, the involved mechanism, and the further effects on modulation of TNBC cell migration and ●NO-induced vasodilation. Multiple formulations were synthesised, and their properties were adjusted to create biodegradable hydrogels with customized compositions and ●NO-scavenging strength, utilizing surface functional ●NO-scavenging molecules. The hydrogel formulations continuously released active ●NOscavenging molecules, particularly of hemin and its derivative, hemin-tyrosine, which were evaluated in vitro. The ●NO-scavenging properties of certain hydrogels and their products following degradation were accompanied by an ability to decrease the levels of intracellular ●NO and inhibit TNBC cell migration. After collecting these observations, the final step was to develop chemically crosslinked HA-hydrogels with tuneable properties and ●NO-scavenging efficiency. This thesis aims to explore a fresh approach to treating TNBC by targeting one of the main gasotransmitters that play a critical molecular role in cancer metastasis. This study synthesised a new class of functional compounds and hydrogels that can scavenge ●NO and regulate cancer cell migration and angiogenesis. The chemical properties of the synthesized compounds and their ●NO-scavenging efficiencies were evaluated, and the further cellular effects were also assessed in vitro and in vivo. Candidate hydrogel formulations, loaded with candidate ●NO-scavenging compounds, were developed, and their reactivity against ●NO was verified by various assays, including in vitro studies.2027-07-1
Enabling Biomaterials for New Biomedical Technologies and Clinical Therapies
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Therapeutic glucose responsive dual gene delivery system for diabetic wound healing
No full textDiabetic wound is a severe and multifactorial pathology that results from hyperglycemia. Despite intensive treatment regimes, there has been limited success in promoting diabetic wound healing. Gene therapy demonstrates significant potential in treating a range of life-threatening diseases and conditions. Employing a glucose responsive gene delivery system as a method of treating diabetic wounds represents an innovative approach. The primary aim of this thesis was to design and fabricate a glucose responsive dual gene delivery system and subsequently evaluate its therapeutic potential in promoting diabetic wound healing in a genetically diabetic mice animal model. The fabricated system comprised two scaffolds: fibrin hollow microcapsules and glucose responsive fibrin hydrogel. The fibrin microcapsules were constructed through layer-by-layer assembly on a CaCO3 template, while the glucose responsive fibrin hydrogel was synthesised by adding glucose oxidase enzyme. Both scaffolds were loaded with two separate reporter genes and topically applied to the wounds of the genetically diabetic db/db mice. The group of animals receiving the glucose responsive treatment displayed increased expression of the reporter genes. Most importantly, the fabricated glucose responsive delivery system exhibited significant therapeutic potential, significantly improving diabetic wound healing after seven days post-surgery. Angiogenesis was enhanced, and inflammation was reduced in the glucose responsive treatment group. A total of 23 proteins were altered in the glucose responsive treatment group compared to the non-treated group. Actinin 2, desmin, and MYBPC1 were the most significantly up-regulated proteins in the glucose responsive treatment group. The increased expression of these proteins in the glucose responsive treatment group was validated through immunohistochemistry analysis. The dual gene delivery system that is responsive to glucose, integrated with fibrin, presents itself as a highly promising therapeutic approach for the purpose of normalising diabetic wound healing. The system's cargo may be complemented in order to achieve the desired outcome
Distinct glycosylation in membrane proteins within neonatal versus adult myocardial tissue
No full textMammalian hearts have regenerative potential restricted to early neonatal stage and lost within seven days after birth. Carbohydrates exclusive to cardiac neonatal tissue may be key regulators of regenerative potential. Although cell surface and extracellular matrix glycosylation are known modulators of tissue and cellular function and development, variation in cardiac glycosylation from neonatal tissue to maturation has not been fully examined.In this study, glycosylation of the adult rat cardiac ventricle showed no variability between the two strains analysed, nor were there any differences between the glycosylation of the right or left ventricle using lectin histochemistry and microarray profiling. However, in the Sprague-Dawley strain, neonatal cardiac glycosylation in the left ventricle differed from adult tissues using mass spectrometric analysis, showing a higher expression of high mannose structures and lower expression of complex N-linked glycans in the three-day-old neonatal tissue. Man(6)GlcNAc(2) was identified as the main high mannose N-linked structure that was decreased in adult while higher expression of sialylated N-linked glycans and lower core fucosylation for complex structures were associated with ageing. The occurrence of mucin core type 2 O-linked glycans was reduced in adult and one sulfated core type 2 O-linked structure was identified in neonatal tissue. Interestingly, O-linked glycans from mature tissue contained both N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), while all sialylated N-linked glycans detected contained only Neu5Ac.As glycans are associated with intracellular communication, the specific neonatal structures found may indicate a role for glycosylation in the neonatal associated regenerative capacity of the mammalian heart. New strategies targeting tissue glycosylation could be a key contributor to achieve an effective regeneration of the mammalian heart in pathological scenarios such as myocardial infarction. (C) 2019 The Author(s). Published by Elsevier B.V
Integrated proteomic and systems biology approach to understanding injured spinal cord pathophysiology and repair
No full textSpinal cord injury (SCI) is a severe neurological condition. There are currently no effective treatment options to restore function following SCI. The major obstacle to developing effective therapies is the fragmented state of our understanding of the complex SCI pathophysiology, its response to potential interventions (e.g. biomaterial therapy) and the differential response to lesion between regenerative and non-regenerative SCI models. To develop mechanisms based therapeutic approaches to spinal cord repair more objective, quantitative, and uniform measures of various pathological and regenerative events triggered by SCI are needed. To address these issues, a multi-model in vivo experimental SCI paradigm was established and compared in this thesis. To study the stimulated repair process as a function of a potential intervention, a biomimetic-aligned collagen hydrogel bridge was developed and tested in a rat SCI model. To study the natural repair process, an injury-induced regenerative paradigm, corresponding to SCI in the regenerative stage of Xenopus was established and characterized. To study the pathophysiological response, an injury-induced degenerative paradigm corresponding to SCI in the non-regenerative stage of Xenopus and in the rat model was employed. This enabled to systematically profile proteome dynamics during natural repair, stimulated repair and degeneration of the spinal cord. Bioinformatics analysis revealed unique protein subsets specifically enriched in each experimental paradigm providing a rich resource of molecular targets for functional validation and for designing new therapeutic strategies. By integrating multiple protein expression datasets and using systems biology tools, molecular and cellular processes that govern repair and pathophysiological response post-SCI were assembled into a framework to provide a holistic view. The systems biology analysis revealed that cellular proteome and metabolic reprogramming is an early response to injury in the regenerative model. The non-regenerative SCI models fail to regulate similar response upon injury. On the other hand, notable parallels between the non-regenerative models across the species were revealed, including strong enrichment of lipid metabolism, activation of lipid accumulation and inflammatory response and suppression of autophagy (an evolutionary conserved mechanism essential for lipid homeostasis) and lipophagy (autophagic degradation of lipid) representing co-ordinated molecular pathological events. Lipids such as cholesterol were identified as the potential regulatory factors underlying maladaptive inflammatory response in the non-regenerative SCI model. The absence of these events during natural repair process suggest their major role in driving pathophysiological response post-SCI. Thus, the integrative analyses converged on an evolutionarily conserved set of biological processes associated with SCI pathophysiology. Finally, these objective measures of pathological events from protein expression data also revealed that incorporation of aligned collagen hydrogel bridges into the SCI microenvironment attenuates the neurodegeneration and microglial activation and responds to injury-induced lipid accumulation by activating proteins (APOE), biological function (lipid efflux) and pathway (LXR/RXR activation in macrophages) involved in lipid homeostasis and anti-inflammation. The unexpected link between lipid metabolism, lipid accumulation and autophagy and tissue degeneration provides new leads for the development of therapeutic targets for improving spinal cord repair.2024-03-0
A developmental glycobiology approach to formulate an enhanced hyaluronic acid-based hydrogel for intervertebral disc regeneration
No full textIntervertebral disc degeneration (IDD) is the leading cause of lower back pain, which affects the majority of the world population at some point in their lives. IDD is a progressive event marked by inflammation, loss of cellularity, extracellular matrix degradation, loss of water, and structural deterioration. Standard care includes symptom management, pain relief, and invasive surgeries in advanced cases. Addressing the need for regenerative therapeutic approaches, scientists have shifted their focus on the properties of a unique population of cells in the nucleus pulposus (NP) region of the intervertebral disc (IVD). Notochordal cells (NC) developmentally descend from the notochord before transitioning into what is identified as NP cells after maturity and age. Some animals, such as pigs and non-chondrodystrophic dogs, retain this population throughout their lives, while humans lose it after NP maturation. The changes that occur in the disc, including the loss of NCs, coincide with the pattern leading to degeneration, which suggests that the notochordal cells and their niche have a role in keeping IVD healthy. To understand these mechanisms better, molecular aspects of degeneration and maturation must be studied.
One overlooked subject in this regard is glycosylation. It is known that heavily glycosylated molecules are involved in disc degeneration. Considering the loss of NCs and the inflammatory changes that occur during the degeneration of the disc, it is hypothesised that introducing the healthy and young NP glycome within a supportive anti-inflammatory hydrogel network could induce changes in the disc that are indicative of tissue remodelling and regeneration. This study identified the glycosylation patterns in young and mature NPs that are rich in notochordal cells. A thorough analysis of the ultra-performance liquid chromatography (UPLC) and mass spectrometry (MS) data revealed over 300 N-glycan species in the NP, more than 45% of which are sialylated and/or fucosylated. In addition, 5% increase α(1,2/3) fucosylation and 9% decrease in α(2,3) sialylation was detected at maturation. With these properties in mind, a hyaluronic acid (HA) hydrogel network was formulated by crosslinking the carboxylic groups of HA with 8-arm polyethylene glycol (PEG), which was enhanced with the notochordal cell-derived matrix (NCM) to mimic the notochordal niche. This HA-NCM formulation formed a hydrogel within 15 minutes. The fabricated hydrogel showed high swelling capacity (up to 150% in weight), and supported cells such as NPs, NCs and stem cells for at least 14 days. The hydrogel also showed signs of mitigating the pro-inflammatory cytokines in the long-term. To test the regenerative potential of the HA-NCM hydrogel system, the last phase of the project investigated an in vivo study utilising a rat-rail model after introducing an acute injury to the NP. Even though the injury created is more than what is expected in the natural course of IDD, the HA-NCM hydrogel can improve the disc height by 36% after injury.
The work described in this thesis introduces a significant potential of a glycomic approach to a clinical problem. Future studies include more robust and efficient methods to analyse the glycosylation patterns and further charcaterisation of NCM to validate its potential while focusing on the mechanistic approaches to induce regeneration and remodelling of the IVD
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