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The Emerging Role of Exosome Nanoparticles in Regenerative Medicine
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Zahra Sadat Hashemi, Mahlegha Ghavami, Saeed Khalili, Seyed Morteza Naghib
For clinical translation of cell-free therapy, the determination of optimal culture conditions is very important. The hypoxic precondition of MSCs can augment their therapeutic potentials. It also could enhance the performance of MSCs transplantation for MI treatment by miRNA regulation (Hu et al. 2016). The myocardial repair benefits of exosomes derived from hypoxia-treated MSCs (ExoH) was compared with the normoxia-treated MSC (ExoN) culture condition. ExoH has considerably increased the angiogenesis, cardiomyocyte viability, and trigger of cardiac progenitor cells (CPC) in the infarcted heart. The microRNA expression analysis demonstrated the upregulation of miR-210 levels in exosome and their parental cells. This property can largely be attributed to the superior pro-angiogenic and cardio-protective capability of exosomes cultured in hypoxia condition. Therefore, hypoxia preconditioning offers an efficient method to maximise the restorative effects of MSC-derived exosomes for CVD (Zhu et al. 2018). In a similar study, Agarwal and co-workers investigated the impact of donor age (neonates, infant, and child) and hypoxia level in the regenerative capability of exosomes derived from human paediatric CPC in a rat model of myocardial IRI. The findings have demonstrated that the exosomes derived from hypoxic and normal conditions boosted cardiac function through decreased fibrosis and promoted angiogenesis. However, exosomes obtained from older ages only implemented restoration ability when CPCs were cultured in hypoxic conditions (Agarwal et al. 2017).
Metabolic Engineering
Published in Jean F. Challacombe, Metabolic Pathway Engineering, 2021
A new approach that shows promise in overcoming the limitations in cellular physiology is the design and use of cell-free systems through synthetic biochemistry approaches, which include a purified activity approach where the enzymes of interest are expressed and purified separately and then mixed together with any required substrates and cofactors [204]. In the alternative lysate approach, the enzymes are expressed in cells, which are lysed to release the enzymes that are used directly without the need for purification [204]. Cell-free systems are currently used for transcription and translation, and the polymerase chain reaction (PCR), which is the basis for amplification of nucleic acids is currently performed as a cell-free system [203]. Another example is the rapid prototyping of regulatory elements, molecular biosensors, and circuits that can be accomplished in cell-free environments [203]. Other current applications for cell-free systems include the production of therapeutic proteins, such as antibodies, vaccine antigens, antimicrobials, and small molecule therapeutics [203], as well as biohydrogen production, sugar metabolism, and terpene production [204]. Some of the advantages of cell-free systems are due to their simplicity compared to actual cells, offering fewer restrictions for pathway design and more control over reaction conditions where enzyme kinetic parameters can be measured over time, and this enables fine-tuning of the system to produce higher yields of the desired products [204].
Protein Expression Methods
Published in Jay L. Nadeau, Introduction to Experimental Biophysics, 2017
In vitro. In vitro expression or cell-free expression systems come in two varieties: translation-only systems and transcription–translation system. The translation only system takes RNA, which can be produced from a in vitro transcription kit, to protein, while the transcription–translation kits are capable of taking vector DNA directly to protein. Cell-free lysates for protein expression are available from a wide variety of organisms including Escherichia coli, wheat germ, and rabbit reticulocytes, which allow for the production of fully functional and modified proteins. Although in vitro expression typically gives extremely low protein yields, it is useful for the production of small amounts of protein and can be used to easily produce radiolabeled proteins through the incorporation of radiolabeled amino acids (typically 35S-labeled methionine or cysteine).
On the behavior of inhaled fibers in a replica of the first airway bifurcation under steady flow conditions
Published in Aerosol Science and Technology, 2022
Frantisek Lizal, Matous Cabalka, Milan Maly, Jakub Elcner, Miloslav Belka, Elena Lizalova Sujanska, Arpad Farkas, Pavel Starha, Ondrej Pech, Ondrej Misik, Jan Jedelsky, Miroslav Jicha
Fibers can provoke an inflammatory reaction, but they can also directly trigger certain chemical processes. Acute or chronic inflammation is associated with oxidative stress, and the production and release of mediators, such as lysosomal enzymes. The body reaction involves also production of intermediates of arachidonic acid, glutathione S-transferases, proteases, cytokines, growth factors, reactive oxygen species (hydrogen peroxide, superoxide anion, hydroxyl radical) from pulmonary macrophages, neutrophils, and other inflammatory cells. Reactive oxygen species can also be produced in cell-free systems - as a direct chemical reaction between fiber surface and extracellular fluids (Osinubi, Gochfeld, and Kipen 2000). Fibers stimulate the proliferation (rapid reproduction) of epithelial or mesothelial cells and simultaneously, during inflammation, some chemical mediators attract fibroblasts2, which deposits in the lung parenchyma in the area of the irritating fiber. Fibers and mediators of the inflammatory reaction can also damage DNA (genotoxic effect). The pathobiological processes can culminate in the formation of fibrous tissue, which normally occurs during wound healing (fibroplasia), and abnormal (benign or malignant) tissue growth.
Optimal control in a multi-pathways HIV-1 infection model: a comparison between mono-drug and multi-drug therapies
Published in International Journal of Control, 2021
Chittaranjan Mondal, Debadatta Adak, Nandadulal Bairagi
In the previous section, we have presented analysis of multi-pathways HIV-1 infection model with constant controls. The study will be more worthy if the controls are considered to be time dependent. We assume here that all three controls vary with time and consider the cost of antiretroviral drugs and their side effects. cells count decreases as the HIV-1 infection progresses. We, therefore, seek to maximise the number of uninfected cells through controls and at the same time minimise the number of infected cells because cell-to-cell infection increases with the number of infected cells. Also, the number of cell-free virus (released by bursting of an infected cell) increases with the number of infected cells, thereby increasing the cell-free infection.
Serum microRNA profiles among dioxin exposed veterans with monoclonal gammopathy of undetermined significance
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Weixin Wang, Youn K. Shim, Joel E. Michalek, Emily Barber, Layla M. Saleh, Byeong Yeob Choi, Chen-Pin Wang, Norma Ketchum, Rene Costello, Gerald E. Marti, Robert F. Vogt, Ola Landgren, Katherine R. Calvo
In MM patients, dysregulated expression of microRNAs (miRNAs) was previously characterized in bone marrow plasma cells (Lionetti et al. 2009; Pichiorri, Suh, and Ladetto 2008; Roccaro et al. 2009) with fewer studies reported on circulating miRNAs in serum (Kubiczkova et al. 2014; Wang et al. 2015). miRNAs are highly conserved small (19-25nt) non-coding RNAs that are involved with post-transcriptional regulation of gene expression (Bartel 2004). miRNAs bind to the 3ʹ untranslated region of target messenger RNA (mRNA), leading to degradation of the mRNA or attenuation of protein translation. miRNAs are important in the regulation of homeostatic processes such as cell proliferation, differentiation, and apoptosis (Calvo et al. 2011; Izumiya et al. 2011; Raveche et al. 2007; Wang et al. 2012). Cell-free miRNAs in blood and body fluids arise from exosomes or microvesicles released from cells into the circulation or from cell lysis (Zhang et al. 2015). Unlike mRNAs, miRNAs are resistant to RNA degradation and are relatively stable under harsh conditions, including storage temperature and time, and repeated freeze-thaw cycles (Gilad et al. 2008; Grasedieck et al. 2012; Mitchell et al. 2008). Several studies explored the potential of circulating miRNAs as biomarkers for various cancers, including hematological cancers (Etheridge et al. 2011; Federico et al. 2019; Grasedieck et al. 2013; Hayes, Peruzzi, and Lawler 2014). However, circulating miRNA in MGUS has not been well characterized.