A major challenge in regenerative medicine is to improve therapeutic cells' delivery and targeting using an efficient and simple protocol. Mesenchymal stem cells (MSC) are currently employed for the ...treatment of inflammatory-based diseases, due to their powerful immunosoppressive potential. Here we report a simple and versatile method to transiently overexpress the hyaluronic acid (HA) receptor, CD44, on MSC membranes, to improve their homing potential towards an inflammatory site without affecting their behavior. The effect of HA-coatings on murine MSC was functionally determined both, in vitro and in vivo as a consequence of the transient CD44 overexpression induced by HA. Data obtained from the in vitro migration assay demonstrated a two-fold increase in the migratory potential of HA-treated MSC compared to untreated cells. In an LPS-induced inflamed ear murine model, HA-treated MSC demonstrated a significantly higher inflammatory targeting as observed at 72 hrs as compared to untreated cells. This increased accumulation for HA-treated MSC yielded a substantial reduction in inflammation as demonstrated by the decrease in the expression of pro-inflammatory markers and by the induction of a pro-regenerative environment.
Scaffolds functionalized with delivery systems for the release of growth factors is a robust strategy to enhance tissue regeneration. However, after implantation, macrophages infiltrate the scaffold, ...eventually initiating the degradation and clearance of the delivery systems. Herein, it is hypothesized that fully embedding the poly(d,l‐lactide‐co‐glycolide acid) microspheres (MS) in a highly structured collagen‐based scaffold (concealing) can prevent their detection, preserving the integrity of the payload. Confocal laser microscopy reveals that non‐embedded MS are easily internalized; when concealed, J774 and bone marrow‐derived macrophages (BMDM) cannot detect them. This is further demonstrated by flow cytometry, as a tenfold decrease is found in the number of MS engulfed by the cells, suggesting that collagen can cloak the MS. This correlates with the amount of nitric oxide and tumor necrosis factor‐α produced by J774 and BMDM in response to the concealed MS, comparable to that found for non‐functionalized collagen scaffolds. Finally, the release kinetics of a reporter protein is preserved in the presence of macrophages, only when MS are concealed. The data provide detailed strategies for fabricating three dimensional (3D) biomimetic scaffolds able to conceal delivery systems and preserve the therapeutic molecules for release.
To avoid clearance of drug delivery systems from 3D scaffolds, a novel biomimetic approach is proposed. A “concealing” strategy is developed, by cloaking poly(lactic‐co‐glycolic acid) microspheres with the type I collagen matrix of a 3D scaffold. This preserves the release kinetics of the bioactive molecules, controlling the production of inflammatory mediators.
Avoiding the clearance of drug delivery systems from 3D scaffolds is crucial to preserve the bioactivity of their therapeutic payload. This is accomplished on page 1479, by E. Tasciotti and ...co‐workers, through a “concealing” strategy: cloaking PLGA microspheres with the type I collagen matrix of a biomimetic scaffold, which enables the control of the production of inflammatory mediators.
A systematic retrospective case note review was undertaken to investigate autism diagnostic factors in 124 individuals with Sturge-Weber syndrome (SWS). Social Responsiveness Scale questionnaires ...were then analysed to explore the severity and profile of autism characteristics in 70 participants. Thirty-two to forty percent of participants had a clinical diagnosis of autism and half of those without a diagnosis showed significant social communication difficulties. Children had a relative strength in social awareness and social motivation, which are typically much reduced in people with autism. This finding may explain why, to date, the diagnosis has often been overlooked in this population. The research therefore suggests that children with Sturge-Weber should be screened to identify social communications difficulties and provided with timely support.
This study of children with Sturge-Weber syndrome (SWS) profiled neurological presentations; compared patients with (+) and without (−) port-wine stain (PWS); and determined risk factors for ...intellectual and language impairments.
A retrospective case note review was conducted at a national centre.
This cohort (n = 140, male 72, median follow up 114 months) showed sex parity. Intellectual disability (“ID”: IQ ≤ 70) affected half (66), being severe (IQ ≤ 40) in two-fifths (27) with ID. Language disorder (core score≤70) affected half (57). Neurological presentations were: status epilepticus 57% (80), hemiplegia 58% (81), headaches 36% (50) and acutely acquired neurological deficits lasting over 24 h 40% (56). One-seventh (20) were PWS(−). This group had: fewer lobes with angioma (p < 0.0001); and less frequent ID (p = 0.002) or language disorder (p = 0.013). Seizure frequency and status epilepticus prevalence did not differ from PWS(+).
ID and language disorder were associated with: more lobes with angioma; earlier seizure onset; more frequent status epilepticus and seizure clusters. On multivariable analysis recurrent status epilepticus (p = 0.037) and multi-lobe involvement (p = 0.002) increased the risk of severe intellectual disability. Active epilepsy was associated with language disorder (p = 0.030).
This is the largest reported series documenting detailed developmental profiles of children with SWS, including ID and ASD. PWS(+) shows high rates of ID and language disorder. PWS(−) SWS has a more favourable outcome. Cognitive outcome is contingent on number of affected lobes and bilateral involvement. Epilepsy exerts an additional deleterious effect on language and cognition. A high percentage of children have a history of status epilepticus, with evidence that this impacts language and cognitive outcomes. Acutely acquired neurological deficits did not penalise either. Regular structured clinical and developmental assessment permit greater identification of neurological and neurodevelopmental impairments in SWS, and appropriate support.
•The main influence on the development of language and intellectual functioning is the extent of the brain abnormality.•The occurrence of seizures in the final year of assessment significantly predicts a language disorder.•The earlier onset of seizures is associated with more severe intellectual and language impairment.•The prevalence of severe intellectual disability is greater in patients who have multiple episodes of status epilepticus.•Patients who lack a port-wine stain have limited cortical involvement, and better developmental outcome despite epilepsy.
Bone is a dynamic organ where skeletal progenitors and hematopoietic cells share and compete for space. Presumptive mesenchymal stem cells (MSC) have been identified and harvested from the bone ...marrow (BM-MSC) and cortical bone fragments (CBF-MSC). In this study, we demonstrate that despite the cells sharing a common ancestor, the differences in the structural properties of the resident tissues affect cell behavior and prime them to react differently to stimuli. Similarly to the bone marrow, the cortical portion of the bone contains a unique subset of cells that stains positively for the common MSC-associated markers. These cells display different multipotent differentiation capability, clonogenic expansion, and immunosuppressive potential. In particular, when compared with BM-MSC, CBF-MSC are bigger in size, show a lower proliferation rate at early passages, have a greater commitment toward the osteogenic lineage, constitutively produce nitric oxide as a mediator for bone remodeling, and more readily respond to proinflammatory cytokines. Our data suggest that the effect of the tissue's microenvironment makes the CBF-MSC a superior candidate in the development of new strategies for bone repair.
Abstract
Background
Dried blood spot (DBS) PCR sensitivity for congenital cytomegalovirus (cCMV) screening ranges from 34% to 86%, but it is unclear whether a negative DBS PCR reflects an absence of ...CMV DNAemia or a technical limitation in viral detection by DBS PCR. The objective of this study was to determine the agreement between CMV DNA PCR tests in plasma and DBS among cCMV infected infants.
Methods
This single center retrospective cohort study evaluated infants diagnosed with cCMV infection by urine CMV PCR at age ≤ 21 days due to clinical symptoms, failed newborn hearing screen, or NICU admission screening. Subjects with a plasma CMV PCR test performed within the first month after birth and a newborn CMV DBS PCR test were included in the study. Agreement between the plasma and DBS PCR tests was calculated using Cohen’s kappa coefficient. Clinical characteristics and viral loads were compared between groups with concordant and discordant DBS and plasma PCR tests using the Kruskal-Wallis or Mann-Whitney U test.
Results
70 cCMV infected infants were included in the study. 30 (43%) were female, 51 (73%) were white, 13 (19%) were black, 6 (8%) were other/multiracial, 3 (4%) were Hispanic, and 54 (77%) had symptomatic cCMV infection. 49 (70%) had DBS+/plasma+ PCR; 1 (1.4%) had DBS+/plasma- PCR; 14 (20%) had DBS-/plasma+ PCR; and 6 (9%) had DBS-/plasma- PCR. Groups had similar distributions of sex, race, ethnicity, gestational age, birthweight, birth length, birth head circumference, and symptomatic infection. DBS sensitivity was 71%. Agreement between the tests was fair (κ = 0.348, 95% confidence interval = 0.115-0.581). Of the 20 subjects with DBS- tests, 70% had plasma+ PCR and 30% had undetectable CMV DNA in plasma. Infants with DBS+/plasma+ PCR had significantly higher plasma viral loads compared to those with DBS-/plasma+ PCR (2245 IU/ml 761-5773 vs. 321 IU/ml 165-464, median interquartile range) (p < 0.0001).
Conclusion
In this predominantly symptomatic cohort, DBS PCR identified the majority (71%) of infants with cCMV infection. A negative DBS PCR was associated with either low-level plasma CMV DNAemia that was seen in 20% of cCMV infected infants, or no plasma DNAemia in 9% of infants. These findings may impact the use of DBS as a screening test for cCMV infection.
Disclosures
Alexandra Katherine Medoro, MD, Merck: Grant/Research Support Amy Leber, PhD, Biomeriux: Grant/Research Support|BioRad: Advisor/Consultant|Cephied: Grant/Research Support|Diasorin: Grant/Research Support
Predicting the assembly of multiple proteins into specific complexes is critical to understanding their biological function in an organism, and thus the design of drugs to address their malfunction. ...Consequently, a significant body of research and development focuses on methods for elucidating protein quaternary structure. In silico techniques are used to propose models that decode experimental data, and independently as a structure prediction tool. These computational methods often consider proteins as rigid structures, yet proteins are inherently flexible molecules, with both local side-chain motion and larger conformational dynamics governing their behaviour. This treatment is particularly problematic for any protein docking engine, where even a simple rearrangement of the side-chain and backbone atoms at the interface of binding partners complicates the successful determination of the correct docked pose. Herein, we present a means of representing protein surface, electrostatics and local dynamics within a single volumetric descriptor, before applying it to a series of physical and biophysical problems to validate it as representative of a protein. We leverage this representation in a protein-protein docking context and demonstrate that its application bypasses the need to compensate for, and predict, specific side-chain packing at the interface of binding partners for both water-soluble and lipid-soluble protein complexes. We find little detriment in the quality of returned predictions with increased flexibility, placing our protein docking approach as highly competitive versus comparative methods. We then explore the role of larger, conformational dynamics in protein quaternary structure prediction, by exploiting large-scale Molecular Dynamics simulations of the SARS-CoV-2 spike glycoprotein to elucidate possible high-order spike-ACE2 oligomeric states. Our results indicate a possible novel path to therapeutics following the COVID-19 pandemic. Overall, we find that the structure of a protein alone is inadequate in understanding its function through its possible binding modes. Therefore, we must also consider the impact of dynamics in protein assembly.
Thermoelectric performance of the p-type semiconductor bornite, Cu5FeS4, is greatly enhanced through chemical substitution. Nonstoichiometric materials in which the Cu:Fe ratio and overall ...cation-vacancy content were adjusted are reported, and a figure of merit, ZT = 0.79, is achieved at temperatures as low as 550 K in Cu4.972Fe0.968S4. All materials were synthesized mechanochemically and characterized by powder X-ray diffraction, differential scanning calorimetry (DSC), and thermal and electrical transport property measurements. Single-phase behavior is retained in copper deficient phases, Cu5–x FeS4, for vacancy levels up to x = 0.1, while in materials Cu5+y Fe1–y S4, in which the Cu:Fe ratio is varied while maintaining full occupancy of cation sites, single-phase behavior persists for y ≤ 0.08. Adjusting the Cu:Fe ratio at a constant cation-vacancy level of 0.06 in Cu4.94+z Fe1–z S4, leads to single phases for z ≤ 0.04. DSC measurements indicate the temperature of the intermediate- (2a) to high-temperature (a) phase transition shows a more marked dependence on the Cu:Fe ratio than the lower temperature 4a to 2a transition. The thermoelectric power factor increases almost linearly with increasing Cu(II) content. The maximum figures of merit are obtained for materials with Cu(II) contents in the range 0.10–0.15 (corresponding to 2.0–2.8% Cu(II)), which simultaneously contain ca. 1% of cation vacancies.
Tetrahedrite, Cu12Sb4S13, is an abundant mineral with excellent thermoelectric properties owing to its low thermal conductivity. The electronic and structural origin of the intriguing physical ...properties of tetrahedrite, including its metal‐to‐semiconductor transition (MST), remains largely unknown. This work presents the first determination of the low‐temperature structure of tetrahedrite that accounts for its unique properties. Contrary to prior conjectures, the results show that the trigonal–planar copper cations remain in planar coordination below the MST. The atomic displacement parameters of the trigonal–planar copper cations, which have been linked to low thermal conductivity, increase by 200% above the MST. The phase transition is a consequence of the orbital degeneracy of the highest occupied 3d cluster orbitals of the copper clusters found in the cubic phase. This study reveals that a Jahn–Teller electronic instability leads to the formation of “molecular‐like” Cu57+ clusters and suppresses copper rattling vibrations due to the strengthening of direct copper–copper interactions. First principles calculations demonstrate that the structural phase transition opens a small band gap in the electronic density of states and eliminates the unstable phonon modes. These results provide insights on the interplay between phonon transport, electronic properties, and crystal structure in mixed‐valence compounds.
Direct copper–copper interactions in tetrahedrite result in the formation of pentameric Cu57+ clusters below the metal‐to‐semiconductor transition. The enhancement of copper–copper interactions in these “molecular‐like” clusters “locks” the trigonal–planar copper cations in place, suppressing the out‐of‐plane rattling vibrations to which low thermal conductivity is attributed.
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