Project description:Amorphous magnesium-substituted calcium phosphate (AMCP) nanoparticles form constitutively in large numbers in the gastrointestinal tract. Collective evidence indicates that they trap luminal macromolecules, such as bacterial and dietary protein antigen, delivering this cargo to mucosal antigen presenting cells. Here using a precise synthetic mimetic of the AMCP nanomineral, we studied whether trapping of macromolecules by AMCP modulates signalling of the macromolecule itself. Based upon whole genome transcriptomic analyses and using peptidoglycan as a macromolecule, we showed that neither AMCP nanomineral itself regulated any gene, nor did it modify any gene regulation by peptidoglycan. We conclude that synthetic AMCP nanomineral can deliver macromolecular cargo intracellularly without affecting gene transcription.
Project description:Regenerating critical-sized long bone defects poses substantial challenges due to limitations of autografts and processed allografts. Biomaterial scaffolds offer versatile alternatives, yet their effectiveness is often constrained by their limited innate osteoinductivity. While growth factors and cells can enhance osteoinduction, the inclusion of biologics in biomaterial scaffolds creates regulatory challenges for clinical translation. To address this, here we describe three-dimensional (3D) printed polycaprolactone (PCL) scaffolds for temporally controlled delivery of osteoimmunomodulatory amorphous calcium phosphate-chitosan nanoparticles (ACPC-NP). In vitro, the ACPC-NP exhibit concentration dependent effects on osteoblasts, monocytes, and osteoclasts. At increasing concentrations up to 500 μg/ml, these nanoparticles stimulate osteogenesis, modulate M2/M1 macrophage polarization, and inhibit osteoclast maturation and activity. Leveraging these concentration-dependent effects in vivo through temporally controlled release of ACPC-NP from 3D-printed PCL scaffolds, we observe the complete regeneration and the restoration of biomechanical strength of critically sized radial defects in rats. Such healing is absent in defects implanted with bare PCL scaffolds or those loaded with calcium-phosphate microparticles. The tunable osteoimmunomodulation by the NP underscore the translational potential of this technology to yield structurally sound and functionally robust bone regeneration outcomes.
Project description:Osteoblasts from 4 donors were seeded onto 20 constructs. Constructs were constructed as described: Calcium phosphate (brushite / β-TCP) posts were pinned into a Sylgard 184 silicone elastomer (base and curing agent, Dow Corning Corporation) base layer in 6-well dishes. Cells were seeded in fibrinogen onto a thrombin gel and subsequently cultured in 3ml of proliferation media (osteoblast media, 50 μg/ml ascorbate-2-phosphate, 40 μg/ml proline) per well until cells had fully contracted the gel between the support posts. Week 0 constructs were harvested and snap-frozen at this point with the remainder transferred to osteogenic media (proliferation media, 10 mM β-glycerophosphate, 10 nM dexamethasone) and harvested at 2, 4, 6 and 8 weeks.
Project description:Amorphous calcium carbonate (ACC) is a non-crystalline form of calcium carbonate, which is composed of aggregated nano-size primary particles. Here, we wanted to evaluate how ACC affects gene expression in a human lung cancer cell line (A549).
Project description:Candida auris is frequently associated with biofilm-related invasive infections. The resistant profile of these biofilms necessitates innovative therapeutic options, where quorum sensing may be a potential target. Farnesol and tyrosol are two fungal quorum-sensing molecules with antifungal effects at supraphysiological concentrations. Here, we performed genome-wide transcript profiling with C. auris biofilms following farnesol or tyrosol exposure using transcriptome sequencing (RNA-Seq). Since transition metals play a central role in fungal virulence and biofilm formation, levels of intracellular calcium, magnesium, and iron were determined following farnesol or tyrosol treatment using inductively coupled plasma optical emission spectrometry. Farnesol caused an 89.9% and 73.8% significant reduction in the calcium and magnesium content, respectively, whereas tyrosol resulted in 82.6%, 76.6%, and 81.2% decrease in the calcium, magnesium, and iron content, respectively, compared to the control. Genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy were primarily affected in treated cells. To prove ergosterol quorum-sensing molecule interactions, microdilution-based susceptibility testing was performed, where the complexation of farnesol, but not tyrosol, with ergosterol was impeded in the presence of exogenous ergosterol, resulting in a minimum inhibitory concentration increase in the quorum-sensing molecules. This study revealed several farnesol- and tyrosol-specific responses, which will contribute to the development of alternative therapies against C. auris biofilms.
Project description:Human genetic diversity can reveal critical factors in host-pathogen interactions. This is especially useful for human-restricted pathogens like Salmonella enterica serovar Typhi (S. Typhi), the cause of Typhoid fever. One key dynamic during infection is competition for nutrients: host cells attempt to restrict intracellular replication by depriving bacteria of key nutrients or delivering toxic metabolites in a process called nutritional immunity. Here, a cellular genome-wide association study of intracellular replication by S. Typhi in nearly a thousand cell lines from around the world—and extensive follow-up using intracellular S. Typhi transcriptomics and manipulation of magnesium concentrations—demonstrates that the divalent cation channel mucolipin-2 (MCOLN2) restricts S. Typhi intracellular replication through magnesium deprivation. Our results reveal natural diversity in Mg2+ limitation as a key component of nutritional immunity against S. Typhi.
