The regeneration of complex tissues and organs remains a major clinical challenge. With a view towards bioprinting such tissues, we developed a new class of pore-forming bioink to spatially and ...temporally control the presentation of therapeutic genes within bioprinted tissues. By blending sacrificial and stable hydrogels, we were able to produce bioinks whose porosity increased with time following printing. When combined with amphipathic peptide-based plasmid DNA delivery, these bioinks supported enhanced non-viral gene transfer to stem cells in vitro. By modulating the porosity of these bioinks, it was possible to direct either rapid and transient (pore-forming bioinks), or slower and more sustained (solid bioinks) transfection of host or transplanted cells in vivo. To demonstrate the utility of these bioinks for the bioprinting of spatially complex tissues, they were next used to zonally position stem cells and plasmids encoding for either osteogenic (BMP2) or chondrogenic (combination of TGF-β3, BMP2 and SOX9) genes within networks of 3D printed thermoplastic fibers to produce mechanically reinforced, gene activated constructs. In vivo, these bioprinted tissues supported the development of a vascularised, bony tissue overlaid by a layer of stable cartilage. When combined with multiple-tool biofabrication strategies, these gene activated bioinks can enable the bioprinting of a wide range of spatially complex tissues.
Display omitted
Avoiding costly fights can help conserve energy needed to survive rapid environmental change. Competitor recognition processes help resolve contests without escalating to attack, yet we have limited ...understanding of how they are affected by resource depletion and potential effects on species coexistence. Using a mass coral mortality event as a natural experiment and 3770 field observations of butterflyfish encounters, we test how rapid resource depletion could disrupt recognition processes in butterflyfishes. Following resource loss, heterospecifics approached each other more closely before initiating aggression, fewer contests were resolved by signalling, and the energy invested in attacks was greater. By contrast, behaviour towards conspecifics did not change. As predicted by theory, conspecifics approached one another more closely and were more consistent in attack intensity yet, contrary to expectations, resolution of contests via signalling was more common among heterospecifics. Phylogenetic relatedness or body size did not predict these outcomes. Our results suggest that competitor recognition processes for heterospecifics became less accurate after mass coral mortality, which we hypothesize is due to altered resource overlaps following dietary shifts. Our work implies that competitor recognition is common among heterospecifics, and disruption of this system could lead to suboptimal decision-making, exacerbating sublethal impacts of food scarcity.
The premise of this article is that climate effects on lakes can be quantified most effectively by the integration of process-oriented limnological studies with paleolimnological research, ...particularly when both disciplines operate within a common conceptual framework. To this end, the energy (E)—mass (m) flux framework (Em flux) is developed and applied to selected retrospective studies to demonstrate that climate variability regulates lake structure and function over diverse temporal and spatial scales through four main pathways: rapid direct transfer of E to the lake surface by irradiance, heat, and wind; slow indirect effects of E via changes in terrestrial development and subsequent m subsidies to lakes; direct influx of m as precipitation, particles, and solutes from the atmosphere; and indirect influx of water, suspended particles, and dissolved substances from the catchment. Sedimentary analyses are used to illustrate the unique effects of each pathway on lakes but suggest that interactions among mechanisms are complex and depend on the landscape position of lakes, catchment characteristics, the range of temporal variation of individual pathways, ontogenetic changes in lake basins, and the selective effects of humans on m transfers. In particular, preliminary synthesis suggests that m influx can overwhelm the direct effects of E transfer to lakes, especially when anthropogenic activities alter m subsidies from catchments.
Though widely hypothesized, limited evidence exists that human brain functions organize in global gradients of abstraction starting from sensory cortical inputs. Hierarchical representation is ...accepted in computational networks, and tentatively in visual neuroscience, yet no direct holistic demonstrations exist in vivo. Our methods developed network models enriched with tiered directionality, by including input locations, a critical feature for localizing representation in networks generally. Grouped primary sensory cortices defined network inputs, displaying global connectivity to fused inputs. Depth-oriented networks guided analyses of fMRI databases (~17,000 experiments;~1/4 of fMRI literature). Formally, we tested whether network depth predicted localization of abstract versus concrete behaviors over the whole set of studied brain regions. For our results, new cortical graph metrics, termed network-depth, ranked all databased cognitive function activations by network-depth. Thus, we objectively sorted stratified landscapes of cognition, starting from grouped sensory inputs in parallel, progressing deeper into cortex. This exposed escalating amalgamation of function or abstraction with increasing network-depth, globally. Nearly 500 new participants confirmed our results. In conclusion, data-driven analyses defined a hierarchically ordered connectome, revealing a related continuum of cognitive function. Progressive functional abstraction over network depth may be a fundamental feature of brains, and is observed in artificial networks.
Controlling the phenotype of mesenchymal stem cells (MSCs) through the delivery of regulatory genes is a promising strategy in tissue engineering (TE). Essential to effective gene delivery is the ...choice of gene carrier. Non-viral delivery vectors have been extensively used in TE, however their intrinsic effects on MSC differentiation remain poorly understood. The objective of this study was to investigate the influence of three different classes of non-viral gene delivery vectors: (1) cationic polymers (polyethylenimine, PEI), (2) inorganic nanoparticles (nanohydroxyapatite, nHA) and (3) amphipathic peptides (RALA peptide) on modulating stem cell fate after reporter and therapeutic gene delivery. Despite facilitating similar reporter gene transfection efficiencies, these nanoparticle-based vectors had dramatically different effects on MSC viability, cytoskeletal morphology and differentiation. After reporter gene delivery (pGFP or pLUC), the nHA and RALA vectors supported an elongated MSC morphology, actin stress fibre formation and the development of mature focal adhesions, while cells appeared rounded and less tense following PEI transfection. These changes in MSC morphology correlated with enhanced osteogenesis following nHA and RALA transfection and adipogenesis following PEI transfection. When therapeutic genes encoding for transforming growth factor beta 3 (TGF-β3) and/or bone morphogenic protein 2 (BMP2) were delivered to MSCs, nHA promoted osteogenesis in 2D culture and the development of an endochondral phenotype in 3D culture, while RALA was less osteogenic and appeared to promote a more stable hyaline cartilage-like phenotype. In contrast, PEI failed to induce robust osteogenesis or chondrogenesis of MSCs, despite effective therapeutic protein production. Taken together, these results demonstrate that the differentiation of MSCs through the application of non-viral gene delivery strategies depends not only on the gene delivered, but also on the gene carrier itself.
Nanoparticle-based non-viral gene delivery vectors have been extensively used in regenerative medicine, however their intrinsic effects on mesenchymal stem cell (MSC) differentiation remain poorly understood. This paper demonstrates that different classes of commonly used non-viral vectors are not inert and they have a strong effect on cell morphology, stress fiber formation and gene transcription in MSCs, which in turn modulates their capacity to differentiate towards osteogenic, adipogenic and chondrogenic lineages. These results also point to the need for careful and tissue-specific selection of nanoparticle-based delivery vectors to prevent undesired phenotypic changes and off-target effects when delivering therapeutic genes to damaged or diseased tissues.
Summary C-type natriuretic peptide (CNP) has been demonstrated in human and mouse models to play critical roles in cartilage homeostasis and endochondral bone formation. Indeed, targeted inactivation ...of the genes encoding CNP results in severe dwarfism and skeletal defects with a reduction in growth plate chondrocytes. Conversely, cartilage-specific overexpression of CNP was observed to rescue the phenotype of CNP deficient mice and significantly enhanced bone growth caused by growth plate expansion. In vitro studies reported that exogenous CNP influenced chondrocyte differentiation, proliferation and matrix synthesis with the response dependent on CNP concentration. The chondroprotective effects were shown to be mediated by natriuretic peptide receptor (Npr)2 and enhanced synthesis of cyclic guanosine-3′,5′-monophosphate (cGMP) production. Recent studies also showed certain homeostatic effects of CNP are mediated by the clearance inactivation receptor, Npr3, highlighting several mechanisms in maintaining tissue homeostasis. However, the CNP signalling systems are complex and influenced by multiple factors that will lead to altered signalling and tissue dysfunction. This review will discuss the differential role of CNP signalling in regulating cartilage and bone homeostasis and how the pathways are influenced by age, inflammation or sex. Evidence indicates that enhanced CNP signalling may prevent growth retardation and protect cartilage in patients with inflammatory joint disease.
OPAL is an English national programme that takes scientists into the community to investigate environmental issues. Biological monitoring plays a pivotal role covering topics of: i) soil and ...earthworms; ii) air, lichens and tar spot on sycamore; iii) water and aquatic invertebrates; iv) biodiversity and hedgerows; v) climate, clouds and thermal comfort. Each survey has been developed by an inter-disciplinary team and tested by voluntary, statutory and community sectors. Data are submitted via the web and instantly mapped. Preliminary results are presented, together with a discussion on data quality and uncertainty. Communities also investigate local pollution issues, ranging from nitrogen deposition on heathlands to traffic emissions on roadside vegetation. Over 200,000 people have participated so far, including over 1000 schools and 1000 voluntary groups. Benefits include a substantial, growing database on biodiversity and habitat condition, much from previously unsampled sites particularly in urban areas, and a more engaged public.
► Environmental research conducted jointly by the public and scientists. ► Over 200,000 people involved, 8000 sites surveyed, uncertainty minimised. ► New insights into urban pollution. ► A more engaged and informed society.
Research is enriched where the public and scientists work together.
ABSTRACT
BACKGROUND
Affirming spaces have been associated with improved mental health outcomes for lesbian, gay, bisexual, transgender, queer, and questioning (LGBTQ) adolescents.
METHODS
With data ...from adolescents currently enrolled in middle or high school across the United States, this study used topic modeling methods to examine students' reports of what they were looking for in LGBTQ‐affirming schools and, separately, the association of LGBTQ‐affirming schools with suicide risk reduction.
RESULTS
Topic models demonstrated consistent themes in how students determined that their school was affirming, such as LGBTQ clubs, teachers requesting pronouns, pride flags, and accepting peers. Students of color uniquely looked for actionable responses in addressing LGBTQ issues. Transgender and nonbinary students required explicit mention of support for transgender issues. Quantitatively, LGBTQ students who reported that their school was LGBTQ‐affirming had 20% lower odds of attempting suicide in the past year (adjusted odds ratio = 0.80).
CONCLUSIONS
These findings suggest that schools must be safe for all youth and implementing policies that make LGBTQ students feel seen and supported in their identities is a protective factor for mental health.
IMPLICATIONS.
School policies must ensure that youth have access to supportive people, symbols of support, and LGBTQ clubs and that they are also salient to LGBTQ students of color and transgender and nonbinary students.
An improved understanding of the spatial distribution of diapycnal mixing in the oceans is the key to elucidating how meridional overturning circulation is closed. The challenge is to develop ...techniques which can be used to determine the variation of diapycnal mixing as a function of space and time throughout the oceanic volume. One promising approach exploits seismic reflection imaging of thermohaline structure. We have applied spectral analysis techniques to fine‐structure undulations observed on a seismic transect close to the Subantarctic Front in the South Atlantic Ocean. 91 horizontal spectra were fitted using a linear combination of a Garrett‐Munk tow spectrum for internal waves and a Batchelor model for turbulence. The fit between theory and observation is excellent and enables us to deduce the spatial variability and context of diapycnal mixing rates, which range from 10−5 to 10−3.5m2s−1.
Oxaliplatin-based chemotherapy can cause hepatic sinusoidal injury (HSI), portal hypertension, and splenic sequestration of platelets. Evidence suggests that bevacizumab may protect against HSI.
Two ...cohorts of metastatic colorectal cancer (CRC) were analyzed: a nonrandomized exploratory cohort of 184 patients treated at a single institution from 2003 to 2010 and a confirmatory cohort of 200 patients from a multi-institutional randomized trial (NO16966). All patients were treated with frontline fluoropyrimidine and oxaliplatin with or without bevacizumab. Changes in splenic volumes and platelet counts were compared by treatment, two-sided log-rank test.
In the exploratory cohort, the bevacizumab-treated patients (n = 138) compared with the nonbevacizumab-treated patients (n = 46) demonstrated a longer median time to splenic enlargement (≥30%, P = .02) and reduced rate of thrombocytopenia (<150 000/mm3, P = .04). In the confirmatory cohort (106 bevacizumab arm and 94 placebo arm), the median time to a spleen enlargement of 30% or more was 7.6 vs 5.4 (P = .01), and six-month cumulative incidence of thrombocytopenia (platelets < 100 000/mm3) was 19% vs 51% (P < .001) for bevacizumab compared with placebo. The development of an increasing spleen size was associated with the risk of either grade 1 or grade 2 thrombocytopenia (P < .001). The cumulative rate of grade 1 or grade 2 thrombocytopenia was statistically less in the bevacizumab arm, with six-month grade 2 thrombocytopenia rates of 4% vs 23% (P < .001). Patients with a large spleen prior to chemotherapy initiation appeared to be at highest risk of this toxicity.
In metastatic CRC, the addition of bevacizumab to oxaliplatin-based chemotherapy reduces the frequency of splenic enlargement and the rate of thrombocytopenia.
PDF
