Functional amyloids produced in bacteria as nanoscale inclusion bodies are intriguing but poorly explored protein materials with wide therapeutic potential. Since they release functional polypeptides ...under physiological conditions, these materials can be potentially tailored as mimetic of secretory granules for slow systemic delivery of smart protein drugs. To explore this possibility, bacterial inclusion bodies formed by a self‐assembled, tumor‐targeted Pseudomonas exotoxin (PE24) are administered subcutaneously in mouse models of human metastatic colorectal cancer, for sustained secretion of tumor‐targeted therapeutic nanoparticles. These proteins are functionalized with a peptidic ligand of CXCR4, a chemokine receptor overexpressed in metastatic cancer stem cells that confers high selective cytotoxicity in vitro and in vivo. In the mouse models of human colorectal cancer, time‐deferred anticancer activity is detected after the subcutaneous deposition of 500 µg of PE24‐based amyloids, which promotes a dramatic arrest of tumor growth in the absence of side toxicity. In addition, long‐term prevention of lymphatic, hematogenous, and peritoneal metastases is achieved. These results reveal the biomedical potential and versatility of bacterial inclusion bodies as novel tunable secretory materials usable in delivery, and they also instruct how therapeutic proteins, even with high functional and structural complexity, can be packaged in this convenient format.
Bacterial inclusion bodies are engineered as secretory amyloids for subcutaneous implantation and physiological release of antitumoral protein drugs. These granules slowly secrete self‐assembling, CXCR4‐targeted protein nanoparticles based on the Pseudomonas exotoxin, which selectively destroys metastatic colorectal cancer stem cells, promoting a dramatic reduction of metastatic foci in the absence of undesired side toxicity.
Under the unmet need of efficient tumor‐targeting drugs for oncology, a recombinant version of the plant toxin ricin (the modular protein T22‐mRTA‐H6) is engineered to self‐assemble as protein‐only, ...CXCR4‐targeted nanoparticles. The soluble version of the construct self‐organizes as regular 11 nm planar entities that are highly cytotoxic in cultured CXCR4+ cancer cells upon short time exposure, with a determined IC50 in the nanomolar order of magnitude. The chemical inhibition of CXCR4 binding sites in exposed cells results in a dramatic reduction of the cytotoxic potency, proving the receptor‐dependent mechanism of cytotoxicity. The insoluble version of T22‐mRTA‐H6 is, contrarily, moderately active, indicating that free, nanostructured protein is the optimal drug form. In animal models of acute myeloid leukemia, T22‐mRTA‐H6 nanoparticles show an impressive and highly selective therapeutic effect, dramatically reducing the leukemia cells affectation of clinically relevant organs. Functionalized T22‐mRTA‐H6 nanoparticles are then promising prototypes of chemically homogeneous, highly potent antitumor nanostructured toxins for precise oncotherapies based on self‐mediated intracellular drug delivery.
One of the most potent protein toxins in nature, ricin, is genetically instructed to self‐assemble as 11 nm homomeric nanoparticles that selectively kill CXCR4‐overexpressing cells. These materials show a potent antitumoral effect when administered to an animal model of the difficult‐to‐treat disseminated acute myeloid leukemia, in complete absence of side toxicity.
Nanoscale protein materials are highly convenient as vehicles for targeted drug delivery because of their structural and functional versatility. Selective binding to specific cell surface receptors ...and penetration into target cells require the use of targeting peptides. Such homing stretches should be incorporated to larger proteins that do not interact with body components, to prevent undesired drug release into nontarget organs. Because of their low interactivity with human body components and their tolerated immunogenicity, proteins derived from the human microbiome are appealing and fully biocompatible building blocks for the biofabrication of nonreactive, inert protein materials within the nanoscale. Several phage and phage‐like bacterial proteins with natural structural roles are produced in Escherichia coli as polyhistidine‐tagged recombinant proteins, looking for their organization as discrete, nanoscale particulate materials. While all of them self‐assemble in a variety of sizes, the stability of the resulting constructs at 37 °C is found to be severely compromised. However, the fine adjustment of temperature and Zn2+ concentration allows the formation of robust nanomaterials, fully stable in complex media and under physiological conditions. Then, microbiome‐derived proteins show promise for the regulatable construction of scaffold protein nanomaterials, which can be tailored and strengthened by simple physicochemical approaches.
The human microbiome is a source of structural proteins useful as protein materials for clinical uses by exploiting their self‐assembling tendencies and the limited interactivity with human molecules. Two phages and one bacterial protein are used to explore this concept, through the controlled formation of regular protein nanoparticles, stable under physiological conditions and suitable for further functionalization.
Aims
To explore the perceptions of nurses on the factors that influence their readiness to manage intimate partner violence (IPV) in Spain.
Design
Qualitative content analysis based on data from six ...different regions in Spain (Murcia, Region of Valencia, Castile and Leon, Cantabria, Catalonia, Aragon) collected between 2014 and 2016.
Methods
37 personal interviews were carried out with nurses from 27 primary health care (PHC) centres and 10 hospitals. We followed the consolidated criteria for reporting qualitative research guidelines. Qualitative content analysis was supported by Atlas.ti and OpenCode.
Results
The results are organised into four categories corresponding to (1) acknowledging IPV as a health issue. An ongoing process; (2) the Spanish healthcare system and PHC service: a favourable space to address IPV although with some limitations; (3) nurses as a key figure for IPV in coordinated care and (4) factors involved in nurses' autonomy in their response to IPV, with their respective subcategories.
Conclusion
In practice, nurses perceive responding to IPV as a personal choice, despite the institutional mandate to address IPV as a health issue. There is a need to increase continuous training and ensure IPV is included in the curriculum in university nursing undergraduate degrees, by disseminating the existing IPV protocols. Furthermore, coordination between healthcare professionals needs to be improved in terms of all levels of care and with other institutions.
Advanced medical treatments involving drug delivery require fully biocompatible materials with the ability to release functional drugs in a time‐prolonged way. Ideally, the delivered molecules should ...be self‐contained as chemically homogenous entities to prevent the use of potentially toxic scaffolds or hold matrices. In nature, peptidic hormones are self‐stored in protein‐only secretory granules formed by the reversible coordination of Zn2+ and histidine residues. Inspired by this concept, an in vitro transversal procedure is developed, analyzed, and comparatively applied for the fabrication of protein‐only secretory granules at the microscale. These materials can be produced from any polyhistidine‐tagged protein using physiological concentrations of Zn2+ as a potent and versatile glue‐like agent. The screening of granules formed by 12 engineered and nonengineered proteins at different Zn2+ concentrations revealed optimal fabrication conditions and the consequent release profiles. Moreover, the functional and structural properties of the delivered protein are fully validated using a drug‐targeting protein platform in a mouse model of human colorectal cancer. In summary, short histidine tags allow the packaging of structurally and functionally dissimilar polypeptides, which supports the proposed fabrication method as a powerful protocol extensible to diverse clinical scenarios in which slow protein drug delivery is required.
Novel microscale protein materials are proposed as mechanically stable secretory granules. Using ionic Zn to cluster histidine‐rich polypeptides keeps their functionality and allows their further slow release under physiological conditions. The versatility to control protein clustering and release profile supports the development of such materials as new biocompatible and disintegrable delivery systems for time‐sustained administration of protein drugs.
In cirrhosis, intestinal dysbiosis, intestinal barrier impairment, and systemic immune system abnormalities lead to gut bacterial translocation (GBT) and bacterial infection. However, intestinal ...immune system dysfunction and its contribution to barrier damage are poorly understood. This study correlates immune system dysregulation in the intestines of rats at different stages of CCl4‐induced cirrhosis with barrier function and pathogenic microbiota. The following variables were addressed in the small intestine: intraepithelial lymphocyte (IEL) and lamina propria lymphocyte (LPL) activation status and cytokine production (flow cytometry), cytokine mRNA and protein expression (quantitative real‐time PCR and immunofluorescence), microbiota composition of ileum content (16S recombinant DNA massive sequencing), permeability (fecal albumin loss), and epithelial junctions (immunohistochemistry and immunofluorescence). The intestinal mucosa in rats with cirrhosis showed a proinflammatory pattern of immune dysregulation in IELs and LPLs, which featured the expansion of activated lymphocytes, switch to a T helper 1 (Th1) regulatory pattern, and Th17 reduction. In rats with cirrhosis with ascites, this state was associated with epithelial junction protein disruption, fecal albumin loss, and GBT. Direct correlations (P < 0.01) were observed between elevated interferon gamma (IFNγ)‐expressing T cytotoxic LPLs and fecal albumin and between inflammatory taxa abundance and IFNγ‐producing immune cells in the ileum. Bowel decontamination led to redistributed microbiota composition, reduced proinflammatory activation of mucosal immune cells, normalized fecal albumin levels, and diminished GBT; but there were no modifications in Th17 depletion. Conclusion: The intestinal mucosa of rats with cirrhosis acquires a proinflammatory profile of immune dysregulation that parallels the severity of cirrhosis; this impaired intestinal immune response is driven by gut dysbiosis and leads to disrupted barrier function, promoting GBT.
Horizontal gene transfer (HGT) among flowering plant mitochondria occurs frequently and, in most cases, leads to nonfunctional transgenes in the recipient genome. Parasitic plants are particularly ...prone to this phenomenon, but their mitochondrial genomes (mtDNA) have been largely unexplored.
We undertook a large-scale mitochondrial genomic study of the holoparasitic plant Lophophytum mirabile (Balanophoraceae). Comprehensive phylogenetic analyses were performed to address the frequency, origin, and impact of HGT.
The sequencing of the complete mtDNA of L. mirabile revealed the unprecedented acquisition of host-derived mitochondrial genes, representing 80% of the protein-coding gene content. All but two of these foreign genes replaced the native homologs and are probably functional in energy metabolism. The genome consists of 54 circular-mapping chromosomes, 25 of which carry no intact genes.
The likely functional replacement of up to 26 genes in L. mirabile represents a stunning example of the potential effect of rampant HGT on plant mitochondria. The use of hostderived genes may have a positive effect on the host–parasite relationship, but could also be the result of nonadaptive forces.
The lysyl oxidase-like protein 2 (LOXL2) contributes to tumour progression and metastasis in different tumour entities, but its role in pancreatic ductal adenocarcinoma (PDAC) has not been evaluated ...in immunocompetent in vivo PDAC models.
Towards this end, we used PDAC patient data sets, patient-derived xenograft in vivo and in vitro models, and four conditional genetically-engineered mouse models (GEMMS) to dissect the role of LOXL2 in PDAC. For GEMM-based studies,
;
;
mice (KPC) and the
;
mice (KC) were crossed with
allele floxed mice (
) or conditional
overexpressing mice (R26
) to generate KPCL2
or KCL2
and KPCL2
or KCL2
mice, which were used to study overall survival; tumour incidence, burden and differentiation; metastases; epithelial to mesenchymal transition (EMT); stemness and extracellular collagen matrix (ECM) organisation.
Using these PDAC mouse models, we show that while
ablation had little effect on primary tumour development and growth, its loss significantly decreased metastasis and increased overall survival. We attribute this effect to non-cell autonomous factors, primarily ECM remodelling.
overexpression, on the other hand, promoted primary and metastatic tumour growth and decreased overall survival, which could be linked to increased EMT and stemness. We also identified tumour-associated macrophage-secreted oncostatin M (OSM) as an inducer of LOXL2 expression, and show that targeting macrophages in vivo affects
and
expression and collagen fibre alignment.
Taken together, our findings establish novel pathophysiological roles and functions for LOXL2 in PDAC, which could be potentially exploited to treat metastatic disease.
Sulfur is an essential element in determining the productivity and quality of agricultural products. It is also an element associated with tolerance to biotic and abiotic stress in plants. In ...agricultural practice, sulfur has broad use in the form of sulfate fertilizers and, to a lesser extent, as sulfite biostimulants. When used in the form of bulk elemental sulfur, or micro- or nano-sulfur, applied both to the soil and to the canopy, the element undergoes a series of changes in its oxidation state, produced by various intermediaries that apparently act as biostimulants and promoters of stress tolerance. The final result is sulfate S
, which is the source of sulfur that all soil organisms assimilate and that plants absorb by their root cells. The changes in the oxidation states of sulfur S
to S
depend on the action of specific groups of edaphic bacteria. In plant cells, S
sulfate is reduced to S
and incorporated into biological molecules. S
is also absorbed by stomata from H
S, COS, and other atmospheric sources. S
is the precursor of inorganic polysulfides, organic polysulfanes, and H
S, the action of which has been described in cell signaling and biostimulation in plants. S
is also the basis of essential biological molecules in signaling, metabolism, and stress tolerance, such as reactive sulfur species (RSS), SAM, glutathione, and phytochelatins. The present review describes the dynamics of sulfur in soil and plants, considering elemental sulfur as the starting point, and, as a final point, the sulfur accumulated as S
in biological structures. The factors that modify the behavior of the different components of the sulfur cycle in the soil-plant-atmosphere system, and how these influences the productivity, quality, and stress tolerance of crops, are described. The internal and external factors that influence the cellular production of S
and polysulfides vs. other S species are also described. The impact of elemental sulfur is compared with that of sulfates, in the context of proper soil management. The conclusion is that the use of elemental sulfur is recommended over that of sulfates, since it is beneficial for the soil microbiome, for productivity and nutritional quality of crops, and also allows the increased tolerance of plants to environmental stresses.
In the pharmaceutical industry nano-hydrocolloid systems frequently coalesce or present nanoparticle aggregation after a long storage periods. Besides, the lyophilization process used to dry ...nanoparticles (NPs) produces loss of their original properties after dispersion. In this work we evaluated the effect on morphology and physicochemical properties of different protective excipients during drying of bovine serum albumin (BSA) NPs loaded with different concentrations of capsaicin. Capsaicin concentrations of 0, 812, 1625, 2437, and 3250 µg mL
were used; subsequently, NPs were dried with deionized water (DW), NaCl (DN), sucrose (DS), and not dried (ND). We found that ND, DW, and DN treatments showed a negative effect on the NPs properties; while, DS reduced the aggregation and produced the formation of isolated nanoparticles at higher concentrations of capsaicin (3250 µg mL
), improving their circular shape, morphometrical parameters, and ζ-potential. The stability of the BSA-capsaicin NPs was associated to complex capsaicin/amino acid/water, in which GLY/GLN, ALA/HIS, ARG, THR, TYR, and Iso/CYS amino acids are involved in the restructuration of capsaicin molecules into the surface of nanoparticles during the drying process. The secondary nanostructuration in the post-synthesis stage can improve the molecular stability of the particles and the capacity of entrapping hydrophobic drugs, like capsaicin.
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