Stroke is a leading cause of permanent disability world-wide, but aside from rehabilitation, there is currently no clinically-proven pharmaceutical or biological agent to improve neurological ...disability. Cell-based therapies using stem cells, such as dental pulp stem cells, are a promising alternative for treatment of neurological diseases, including stroke. The ischaemic environment in stroke affects multiple cell populations, thus stem cells, which act through cellular and molecular mechanisms, are promising candidates. The most common stem cell population studied in the neurological setting has been mesenchymal stem cells due to their accessibility. However, it is believed that neural stem cells, the resident stem cell of the adult brain, would be most appropriate for brain repair. Using reprogramming strategies, alternative sources of neural stem and progenitor cells have been explored. We postulate that a cell of closer origin to the neural lineage would be a promising candidate for reprogramming and modification towards a neural stem or progenitor cell. One such candidate population is dental pulp stem cells, which reside in the root canal of teeth. This review will focus on the neural potential of dental pulp stem cells and their investigations in the stroke setting to date, and include an overview on the use of different sources of neural stem cells in preclinical studies and clinical trials of stroke.
With emerging resistance to frontline treatments, it is vital that new antimalarial drugs are identified to target Plasmodium falciparum. We have recently described a compound, MMV020291, as a ...specific inhibitor of red blood cell (RBC) invasion, and have generated analogues with improved potency. Here, we generated resistance to MMV020291 and performed whole genome sequencing of 3 MMV020291-resistant populations. This revealed 3 nonsynonymous single nucleotide polymorphisms in 2 genes; 2 in profilin (N154Y, K124N) and a third one in actin-1 (M356L). Using CRISPR-Cas9, we engineered these mutations into wild-type parasites, which rendered them resistant to MMV020291. We demonstrate that MMV020291 reduces actin polymerisation that is required by the merozoite stage parasites to invade RBCs. Additionally, the series inhibits the actin-1-dependent process of apicoplast segregation, leading to a delayed death phenotype. In vitro cosedimentation experiments using recombinant P. falciparum proteins indicate that potent MMV020291 analogues disrupt the formation of filamentous actin in the presence of profilin. Altogether, this study identifies the first compound series interfering with the actin-1/profilin interaction in P. falciparum and paves the way for future antimalarial development against the highly dynamic process of actin polymerisation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The emerging resistance to combination therapies comprised of artemisinin derivatives has driven a need to identify new antimalarials with novel mechanisms of action. Central to the survival and ...proliferation of the malaria parasite is the invasion of red blood cells by Plasmodium merozoites, providing an attractive target for novel therapeutics. A screen of the Medicines for Malaria Venture Pathogen Box employing transgenic P. falciparum parasites expressing the nanoluciferase bioluminescent reporter identified the phenylsulfonyl piperazine class as a specific inhibitor of erythrocyte invasion. Here, we describe the optimization and further characterization of the phenylsulfonyl piperazine class. During the optimization process we defined the functionality required for P. falciparum asexual stage activity and determined the alpha-carbonyl S-methyl isomer was important for antimalarial potency. The optimized compounds also possessed comparable activity against multidrug resistant strains of P. falciparum and displayed weak activity against sexual stage gametocytes. We determined that the optimized compounds blocked erythrocyte invasion consistent with the asexual activity observed and therefore the phenylsulfonyl piperazine analogues described could serve as useful tools for studying Plasmodium erythrocyte invasion.
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•Key structural motifs necessary for asexual parasite potency were identified.•Analogues exhibit potent P. knowlesi and P. falciparum multi-drug resistant potency.•Phenylsulfonyl piperazine class has a unique erythrocyte invasion phenotype.•Optimized analogues are useful tools for studying Plasmodium erythrocyte invasion.
Stem cell-based therapy is a potential alternative strategy for brain repair, with neural stem cells (NSC) presenting as the most promising candidates. Obtaining sufficient quantities of NSC for ...clinical applications is challenging, therefore alternative cell types, such as neural crest-derived dental pulp stem cells (DPSC), may be considered. Human DPSC possess neurogenic potential, exerting positive effects in the damaged brain through paracrine effects. However, a method for conversion of DPSC into NSC has yet to be developed. Here, overexpression of octamer-binding transcription factor 4 (OCT4) in combination with neural inductive conditions was used to reprogram human DPSC along the neural lineage. The reprogrammed DPSC demonstrated a neuronal-like phenotype, with increased expression levels of neural markers, limited capacity for sphere formation, and enhanced neuronal but not glial differentiation. Transcriptomic analysis further highlighted the expression of genes associated with neural and neuronal functions. In vivo analysis using a developmental avian model showed that implanted DPSC survived in the developing central nervous system and respond to endogenous signals, displaying neuronal phenotypes. Therefore, OCT4 enhances the neural potential of DPSC, which exhibited characteristics aligning with neuronal progenitors. This method can be used to standardise DPSC neural induction and provide an alternative source of neural cell types.
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•HT screen identified the triazolopyrimidine class with potent antimalarial activity.•Analogues exhibit potent P. falciparum activity but decreased activity against P. ...knowlesi.•Triazolopyrimidine class has a moderate to slow onset of action against asexual parasites.•Future development of the triazolopyrimidine class hinges on correcting metabolism.
Malaria is a devastating parasitic disease caused by parasites from the genus Plasmodium. Therapeutic resistance has been reported against all clinically available antimalarials, threatening our ability to control the disease and therefore there is an ongoing need for the development of novel antimalarials. Towards this goal, we identified the 2-(N-phenyl carboxamide) triazolopyrimidine class from a high throughput screen of the Janssen Jumpstarter library against the asexual stages of the P. falciparum parasite. Here we describe the structure activity relationship of the identified class and the optimisation of asexual stage activity while maintaining selectivity against the human HepG2 cell line. The most potent analogues from this study were shown to exhibit equipotent activity against P. falciparum multidrug resistant strains and P. knowlesi asexual parasites. Asexual stage phenotyping studies determined the triazolopyrimidine class arrests parasites at the trophozoite stage, but it is likely these parasites are still metabolically active until the second asexual cycle, and thus have a moderate to slow onset of action. Non-NADPH dependent degradation of the central carboxamide and low aqueous solubility was observed in in vitro ADME profiling. A significant challenge remains to correct these liabilities for further advancement of the 2-(N-phenyl carboxamide) triazolopyrimidine scaffold as a potential moderate to slow acting partner in a curative or prophylactic antimalarial treatment.
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•The lipophilicity of analogues was intricately linked to asexual parasite activity.•Analogues exhibit potent activity against P. knowlesi and P. falciparum resistant ...parasites.•2-Anilino-4-amino quinazoline analogues have a fast-killing asexual phenotype.•Optimized analogues reduced parasitemia in mouse model of malaria.
Malaria is a devastating disease caused by Plasmodium parasites. Emerging resistance against current antimalarial therapeutics has engendered the need to develop antimalarials with novel structural classes. We recently described the identification and initial optimization of the 2-anilino quinazoline antimalarial class. Here, we refine the physicochemical properties of this antimalarial class with the aim to improve aqueous solubility and metabolism and to reduce adverse promiscuity. We show the physicochemical properties of this class are intricately balanced with asexual parasite activity and human cell cytotoxicity. Structural modifications we have implemented improved LipE, aqueous solubility and in vitro metabolism while preserving fast acting P. falciparum asexual stage activity. The lead compounds demonstrated equipotent activity against P. knowlesi parasites and were not predisposed to resistance mechanisms of clinically used antimalarials. The optimized compounds exhibited modest activity against early-stage gametocytes, but no activity against pre-erythrocytic liver parasites. Confoundingly, the refined physicochemical properties installed in the compounds did not engender improved oral efficacy in a P. berghei mouse model of malaria compared to earlier studies on the 2-anilino quinazoline class. This study provides the framework for further development of this antimalarial class.
Cellular lipid uptake (through endocytosis) is a basic physiological process. Dysregulation of this process underlies the pathogenesis of diseases such as atherosclerosis, obesity, diabetes, and ...cancer. However, to date, only some mechanisms of lipid endocytosis have been discovered. Here, we show a previously unknown mechanism of lipid cargo uptake into cells mediated by the receptor Mincle. We found that the receptor Mincle, previously shown to be a pattern recognition receptor of the innate immune system, tightly binds a range of self-lipids. Moreover, we revealed the minimal molecular motif in lipids that is sufficient for Mincle recognition. Superresolution microscopy showed that Mincle forms vesicles in cytoplasm and colocalizes with added fluorescent lipids in endothelial cells but does not colocalize with either clathrin or caveolin-1, and the added lipids were predominantly incorporated in vesicles that expressed Mincle. Using a model of ganglioside GM3 uptake in brain vessel endothelial cells, we show that the knockout of Mincle led to a dramatic decrease in lipid endocytosis. Taken together, our results have revealed a fundamental lipid endocytosis pathway, which we call Mincle-mediated endocytosis (MiME), and indicate a prospective target for the treatment of disorders of lipid metabolism, which are rapidly increasing in prevalence.
In potato, phloem tissues transport sugars and signal molecules to the tuber for growth and storage. The CLAVATA3/ESR-like (CLE) family of plant peptides plays an important role in regulating plant ...development. In this study, we identified a set of phloem-expressed CLE genes in Solanum tuberosum L. (StCLEs). We analyzed the phloem transcriptome of potato and found that 10 out of 41 StCLE genes were expressed in phloem cells, with StCLE12 and StCLE19 showing the highest expression levels. StCLE12 has an identical CLE domain to the Arabidopsis TDIF peptides, which are known to play a crucial role in maintaining the vascular meristem. StCLE19 has the highest sequence similarity to the Arabidopsis CLE25 peptide, which is involved in the formation of the phloem element and signaling in response to dehydration stress. The overexpression of StCLE12 and another potato TDIF-like gene, StCLE8, promoted vascular cell proliferation and delayed leaf senescence. On the other hand, plants with overexpression of StCLE19 were unable to form adventitious roots and demonstrated the absence of ordered cambium cell layers in the vascular bundles.
Systemic lupus erythematosus is a chronic, systemic, non-organ-specific autoimmune disease that affects all organs and systems of the human body and is characterized by the production of ...autoantibodies against nuclear antigens. Its prevalence in Europe reaches 1:2500. It affects mostly women (female : male ratio=9 : 1) in fertile age group (15-45 years). The clinical course of lupus in males is characterized by more aggressive clinical course and the development of serious complications, such as vasculitis, central nervous system involvement, antiphospholipid syndrome, etc. For the period of 7 years (2012-2019) we observed overall 18 male patients with systemic lupus, 11 with biopsy-proven renal involvement and 7 without clinically significant renal disease (proteinuria < 0.5 g/24 h., no erythrocyturia/cylindruria, normal renal function), mean age at the diagnosis 39.6 +/- 12.3 years. All patients received pathogenetic treatment (corticosteroids + cytotoxic agents). Three had secondary antiphospholipid syndrome, 1 – inflammatory bowel disease, 1 – seronegative spondyloarthropathy. Three had type 2 diabetes. The authors discuss the clinical, immunological and histological characteristics and the therapeutic approach in males with systemic lupus.
Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but severe drug reaction, most commonly to aromatic anticonvulsants with a delayed onset, variable clinical ...presentation and protracted course. The exact incidence of DRESS syndrome is not known because of the variability in clinical presentation, lack of strict diagnostic criteria and universally accepted nomenclature.
We report four cases of DRESS syndrome associated with the use of carbamazepine. The clinical manifestation was similar: a maculopapular eruption progressing to exfoliative erythroderma, fever, and lymphadenopathy. Leukocytosis, atypical lymphocytes and liver injury (in 2 patients) were also observed. Assessment of causality using the Naranjo algorithm established a “probable” relationship with carbamazepine in three of the cases and a “possible” relationship in one case.
Detection of DRESS syndrome is dependent on the exclusion of a variety of diseases with similar manifestations and may be delayed in time. DRESS syndrome is a potentially life‐threatening multisystem adverse drug reaction, and accidental reexposure or drug provocation tests must be avoided.
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