The processes regulating the generation of proteins from the early translation events to the final biologically active products are complex and tightly controlled ....
Proprotein convertases (PCs) are crucial in the processing and entry of viral or bacterial protein precursors and confer increased infectivity of pathogens bearing a PC activation site, which results ...in increased symptom severity and lethality. Previously, we developed a nanomolar peptide inhibitor of PCs to prevent PC activation of infectious agents. Herein, we describe a peptidomimetic approach that increases the stability of this inhibitor for use in vivo to prevent systemic infections and cellular damage, such as that caused by influenza H5N1 and Shiga toxin. The addition of azaβ(3)-amino acids to both termini of the peptide successfully prevented influenza hemagglutinin 5 fusogenicity and Shiga toxin Vero toxicity in cell-based assays. The results from a cell-based model using stable shRNA-induced proprotein convertase knockdown indicate that only furin is the major proprotein convertase required for HA5 cleavage.
The proprotein convertases (PCs) play an important role in protein precursor activation through processing at paired basic residues. However, significant substrate cleavage redundancy has been ...reported between PCs. The question remains whether specific PC inhibitors can be designed. This study describes the identification of the sequence LLLLRVKR, named Multi-Leu (ML)-peptide, that displayed a 20-fold selectivity on PACE4 over furin, two enzymes with similar structural characteristics. We have previously demonstrated that PACE4 plays an important role in prostate cancer and could be a druggable target. The present study demonstrates that the ML-peptide significantly reduced the proliferation of DU145 and LNCaP prostate cancer-derived cell lines and induced G0/G1 cell cycle arrest. However, the ML-peptide must enter the cell to inhibit proliferation. It is concluded that peptide-based inhibitors can yield specific PC inhibitors and that the ML-peptide is an important lead compound that could potentially have applications in prostate cancer.
Neutrophil myeloperoxidase/H
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/chloride system is a key mechanism to control pathogen infection. This enzyme, myeloperoxidase, plays a pivotal role in the arsenal of azurophilic granules that are ...released through degranulation upon neutrophil activation, which trigger local hypochlorous acid production. Myeloperoxidase gene encodes a protein precursor named promyeloperoxidase that arbors a propeptide that gets cleaved later during secretory routing in post-endoplasmic reticulum compartments. Although evidence suggested that this processing event was performed by one or different enzymes from the proprotein convertases family, the identity of this enzyme was never investigated. In this work, the naturally producing myeloperoxidase promyelocytic cell line HL-60 was used to investigate promyeloperoxidase cleavage during granulocytic differentiation in response to proprotein convertase inhibitors decanoyl-RVKR-chloromethylketone and hexa-d-arginine. Stable PC knockdown of endogenously expressed proprotein convertases, furin and PC7, was achieved using lentiviral delivery of shRNAs. None of the knockdown cell line could reproduce the effect of the pan-proprotein convertases inhibitor decanoyl-RVKR-chloromethylketone that accumulated intracellular promyeloperoxidase stores in HL-60 cells, therefore illustrating that both furin and PC7 redundantly process this proprotein.
Parental depressive symptoms and sensitivity have well-documented consequences for children; however, studies considering both parents are still scarce. This longitudinal study aimed to investigate ...the respective roles of paternal and maternal depressive symptoms and sensitivity in predicting the development of child socioemotional problems during toddlerhood. We also investigated the buffering role of each parent’s sensitivity in the associations between the other parent’s depressive symptoms and toddlers’ socioemotional problems. The sample consisted of 140 Canadian families who were visited in their homes when children were around 13 (T1), 19 (T2), and 27 (T3) months of age. At T1, both parents’ sensitivity was assessed from observations of parent-child interactions at home and each parent reported on his or her own depressive symptoms. At T1, T2, and T3, maternal and paternal perceptions of their toddler’s socioemotional problems were assessed and aggregated. Growth curve analyses revealed that paternal and maternal depressive symptoms as well as paternal sensitivity were unique and persistent predictors of child socioemotional problems and that sensitive fathering acted as a buffer in the context of maternal depressive symptoms. This study highlights the importance of considering both parents when studying risk and protective factors for young children’s socioemotional problems.
Executive functions (EF) play an essential role in many spheres of child development. Therefore, it is crucial to get a better understanding of their etiology. Using a genetic design that involved ...934 twins (400 monozygotic), this study examined the etiology of cognitive flexibility, a component of EF, at 5 years of age and its phenotypic and etiological associations with maternal control. Cognitive flexibility was measured in a laboratory setting at 5 years of age using a well-known EF-task, i.e. the Dimensional Change Card Sort (DCCS). Maternal control was measured using a self-report questionnaire. The univariate genetic model demonstrated that environmental factors mainly explained individual differences in preschoolers' performance on the DCCS task. A bivariate genetic model demonstrated that non-shared environmental mechanisms mainly explained the association (r = .−13) between maternal control and children's performance on the DCCS task. This study represents a preliminary step toward a better understanding of the genetic and environmental contributions underlying the relation between parenting behaviors and children's EF.
The spurious acquisition and optimization of a furin cleavage site in the SARS-CoV-2 spike protein is associated with increased viral transmission and disease, and has generated intense interest in ...the development and application of therapeutic furin inhibitors to thwart the COVID-19 pandemic. This review summarizes the seminal studies that informed current efforts to inhibit furin. These include the convergent efforts of endocrinologists, virologists, and yeast geneticists that, together, culminated in the discovery of furin. We describe the pioneering biochemical studies which led to the first furin inhibitors that were able to block the disease pathways which are broadly critical for pathogen virulence, tumor invasiveness, and atherosclerosis. We then summarize how these studies subsequently informed current strategies leading to the development of small-molecule furin inhibitors as potential therapies to combat SARS-CoV-2 and other diseases that rely on furin for their pathogenicity and progression.
There is increasing interest in the therapeutic targeting of proteases for the treatment of important diseases. Additionally new protein-based therapeutic strategies have the potential to widen the ...available treatments against these pathologies. In the last decade, accumulated evidence has confirmed that the family of proteases known as proprotein convertases (PCs) are potential targets for viral infections, osteoarthritis, cancer and cardiovascular disease, among others. Nevertheless, there are still many unanswered questions about the relevance of targeting PCs in a therapeutic context, especially regarding the anticipated secondary effects of treatment, considering the observed embryonic lethality of some PC knockout mice. In this review, the benefits of PCs as pharmacological targets will be discussed, with focus on concepts and strategies, as well as on the state of advancement of actual and future inhibitors.
Inhibition of PACE4, a proprotein convertase that is overexpressed in prostate cancer, has been shown to block cancer progression in an androgen-independent manner. However, the basis for its ...overexpression and its growth-inhibitory effects are mitigated and uncertain. Here, we report that PACE4 pre-mRNA undergoes DNA methylation-sensitive alternative splicing of its terminal exon 3' untranslated region, generating an oncogenic, C-terminally modified isoform (PACE4-altCT). We found this isoform to be strongly expressed in prostate cancer cells, where it displayed an enhanced autoactivating process and a distinct intracellular routing that prevented its extracellular secretion. Together, these events led to a dramatic increase in processing of the progrowth differentiation factor pro-GDF15 as the first PACE4 substrate to be identified in prostate cancer. We detected robust expression of PACE4-altCT in other cancer types, suggesting that an oncogenic switch for this proenzyme may offer a therapeutic target not only in advanced prostate cancer but perhaps also more broadly in human cancer.
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•Reuterin (3-hyrdoxypropionaldehyde (3-HPA)) is a highly potent metabolite of Lactobacillus reuteri.•Reuterin is highly stable in gastrointestinal condition.•Human colorectal ...adenocarcinoma cells’ viability and membrane integrity remained unaltered by reuterin.•No significant hemolytic activity was detected.•Reuterin is a promising therapeutic and/or food preservative.
Reuterin (3-hyrdoxypropionaldehyde (3-HPA)) is a highly potent metabolite of L. reuteri, which has applications in food, health, and veterinary sectors. Similar to other natural antimicrobial compounds, the approval of reuterin as a bio-preservative or therapeutic agent by regulatory agencies relies on sufficient data on its cytotoxicity and behavior in the gastrointestinal environment. Although the antimicrobial activity of reuterin has been broadly studied, its safety and toxicity are yet to be explored in detail. In this study, the stability and activity of reuterin were investigated in the gastrointestinal tract using in vitro models simulating gastrointestinal conditions. In addition, hemolytic activity and in vitro cytotoxicity of reuterin were evaluated by neutral red assay and lactate dehydrogenase (LDH) colorimetric assay using the same cell line. Activity of reuterin was observed to be stable during gastrointestinal transit. Viability and membrane integrity of cells remained unaltered by reuterin up to 1080 mM concentration. Furthermore, no hemolysis was observed in blood cells exposed to 270 mM reuterin. This study provides unique and highly relevant in vitro data regarding gastrointestinal behavior and toxicity of reuterin. In conclusion, the current study indicates that within a certain concentration range, reuterin can be safely used in bio-preservation and therapeutics applications. However, further in vivo studies are required to confirm these findings.
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