Tumor Spheroids from Monolayer Cultures
Rolf Bjerkvig in Spheroid Culture in Cancer Research, 2017
Due to the homogeneity of the proteins expressed by the host tissue and the tumor cells in vivo, it is impossible to distinguish the synthetic source of the proteins produced as a consequence of tumor invasion. That is, are the ECM components synthesized by the tumor cells or by the host tissue, in response to the presence of either the tumor cells per se or to tumor-secreted factors? It has been demonstrated that the presence of leptomeningeal extracellular matrix proteins are able to inhibit the growth and differentiation of malignant human glioma cells, and this may serve as a mechanism by the host to resist the invasion of tumor cells.49 To attempt to resolve this problem, many studies of extracellular matrix protein expression by particular cell types have been performed using in vitro techniques, and it is beyond the scope of this review to provide an exhaustive list of those findings. It is understood, through the intrinsic properties of the extracellular matrix proteins, that they play an important role in the maintenance of tissue structure and architecture. As a consequence it is therefore of importance to highlight differences obtained in ECM expression between cells grown either as monolayer, multicellular spheroids or as xenografts in vivo.
Order Bunyavirales
Paul Pumpens, Peter Pushko, Philippe Le Mercier in Virus-Like Particles, 2022
Regarding structural proteins, as illustrated in Figure 32.2, the M RNA encodes a single open reading frame that is processed into the viral glycoproteins Gn and Gc, which are embedded into the lipid bilayer envelope of the virion, but the S RNA segment encodes the protein N, which, in addition to encapsidation of the genomic RNAs, functions as an RNA chaperone (for references see a review of Soldan and González-Scarano 2014). Unlike arenaviruses, the hantaviruses do not encode a matrix protein as a possible analogue of the protein Z that played the central role in the generation of arenaviral VLPs. It was speculated that the function of matrix protein in this case is carried out by the cytoplasmic tail of glycoprotein Gn that interacts with the nucleocapsid protein and/or genomic RNA (Strandin et al. 2013).
Infections
Evelyne Jacqz-Aigrain, Imti Choonara in Paediatric Clinical Pharmacology, 2021
The Human Inmmunodeficiency Virus (HIV) is a retrovirus. The virus contains 2 identical copies of a positive sense (i.e. mRNA) single-stranded RNA strand about 9,500 nucleotides long. These may be linked to each other to form a genomic RNA dimer. The RNA dimer is in turn associated with a basic nucleocapsid (NC) protein (p9/6). The ribonucleoprotein particle is encapsidated by a capsid made up of a capsid protein (CA), p24. The capsid environment also contains other viral proteins such as integrase and reverse transcriptase. It also contains a wide variety of other macromolecules derived from the cell including tRNAlys3, which serves as a primer for reverse transcription. The capsid has an icosahedral structure. The capsid is in turn encapsidated by a layer of matrix protein (MA), p17. This matrix protein is associated with a lipid bilayer or envelope.
A tool with many applications: vesicular stomatitis virus in research and medicine
Published in Expert Opinion on Biological Therapy, 2020
Altar M. Munis, Emma M. Bentley, Yasuhiro Takeuchi
The single-stranded, negative-sense RNA genome of VSV encodes five structural proteins: nucleoprotein, phosphoprotein, matrix protein, glycoprotein, and the viral polymerase [8,9] (Figure 1(a)). The matrix protein is responsible for the formation of the viral core and anchoring of the glycoprotein to the viral membrane enabling the formation of glycoprotein homotrimers [10]. The glycoprotein dictates receptor recognition, cell entry, and viral fusion; thus, it is the major target for the humoral immune response [11]. The RNA-dependent RNA polymerase activity for viral replication takes place in the target cell cytosol and is driven by the complex containing the nucleoprotein, viral polymerase, and phosphoprotein [12]. The viral genes are expressed in a single non-segmented negative strand RNA in order [13]. As the transcriptional activity of the 3ʹ promoter is attenuated at each gene junction, 3ʹ genes of the viral genome are transcribed more abundantly [14] (Figure 1(a)).
Targeting Ebola virus replication through pharmaceutical intervention
Published in Expert Opinion on Investigational Drugs, 2021
Frederick Hansen, Heinz Feldmann, Michael A Jarvis
RNPs are subsequently transported to the cell surface in an actin-dependent manner [51,52]. In parallel, the matrix protein VP40 is also transported to the cell surface, where it interacts with cellular trafficking system components such as actin and microtubules [53–56]. The filovirus GP moves to the cell surface through the secretory pathway, where it is post-translationally modified by O- and N-linked glycosylation [57] and furin cleavage into the mature GP1 and GP2 subunits [58]. Finally, VP40 coordinates virion assembly and budding at the plasma membrane supported by host factors such as those of the endosomal complex required for transport (ESCRT) and ubiquitin ligases, which interact with VP40 through its late-domain motifs [59–62]. GP1,2 was shown to facilitate the trafficking of host scramblases to sites of virion budding, thereby enhancing exposure of PtdSer on the outer envelope of virions for binding to PtdSer receptors such as TIM-1 during entry [63].
Photoprotective effect of solid lipid nanoparticles of rutin against UVB radiation damage on skin biopsies and tissue-engineered skin
Published in Journal of Microencapsulation, 2022
Rodrigo Molina Martins, Silvia de Siqueira Martins, Gustavo Luis Ferreira Barbosa, Maria José Vieira Fonseca, Patrick J. Rochette, Véronique J. Moulin, Luis Alexandre Pedro de Freitas
UV irradiation increases MMP expression. that can degrade all components of extracellular matrix protein, including collagen and elastin, resulting in wrinkling and photoaging (Ma et al. 2018, Souza et al. 2018). We have measured the activity of MMPs in UVB irradiated and non-irradiated skin samples after treatment with rutin or the formulation containing SLNs of rutin. UVB irradiation of the skin increased the MMP content by 4-fold compared with the non-irradiated skins (Figure 5(b)). The formulation containing rutin or SLNs of rutin decreased the MMP content to the non-irradiated skin level. Those results suggest that the photochemopreventive effect of SLNs of rutin incorporated in topical formulation could balance the establishment of oxidative stress by decreasing lipid peroxidation and the activity of MMPs.
Related Knowledge Centers
- Filoviridae
- Herpesviridae
- Orthomyxoviridae
- Paramyxoviridae
- Retrovirus
- Viral Envelope
- Virus
- Influenza
- Nucleoprotein
- M1 Protein