Expression of NF-κB in Schwann cells and its effect on motor neuron apoptosis in spinal cord following sciatic nerves injury in rats

Objective：To explore the expression of nuclear factor-kappa B （NF-kB） in Schwann cells （SCs） and its effect on motor neuron apoptosis in spinal cord following sciatic nerves injury in adult rats. Methods： Thirty-six adult Sprague-Dawley （SD） rats were divided randomly into normal control group （n=6）, and sciatic nerves crushing group （n= 30）, and the later was further equally randomized into 5 subgroups： 1, 3, 7, 14, and 21 d post-injury groups. The expression of NF-kB of normal and injured nerves were examined by immunohistochemistry staining, and the apoptosis of motor neurons in spinal cord of lumbar 4 to lumbar 6 （L4-L6） was investigated by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling （TUNEL） assay. Both were qua.ntitated by image analysis. Results： In crushing group, except 21 d post-injury group, the expression of NF-kB was markedly higher than that in the normal control group （P〈0.05, P〈0. 01）. At 1 d after sciatic nerves crushing, the expression of NF-kB was obviously up-regulated, reached peak at 3 d, and recovered at 21 d. The same trend was observed in the time-course on motor neuron apoptosis after sciatic nerves injury. Correlation analyses revealed that motor neuron apoptosis was significantly and positively correlated with the expression of NF-kB following sciatic nerves injury （r= 0. 976 0, P〈0. 01）. Conclusion： After injury of sciatic nerves, the presence and up-regulation of NF-kB in SCs may be involved in motor neuron apoptosis in L4-L6 spinal cord.

Cowpea NAC1/NAC2 transcription factors improve growth and tolerance to drought and heat in transgenic cowpea through combined activation of photosynthetic and antioxidant mechanisms

NAC(NAM/ATAF1/2/CUC2)transcription factors are central switches of growth and stress responses in plants.However,unpredictable interspecies conservation of function and regulatory targets makes the well-studied NAC orthologs inapt for pulse engineering.The knowledge of suitable NAC candidates in hardy pulses like cowpea(Vigna unguiculata(L.)Walp.)is still in infancy,hence warrants immediate biotechnological intervention.Here,we showed that overexpression of two native NAC genes(VuNAC1and VuNAC2)promoted germinative,vegetative,and reproductive growth and conferred multiple abiotic stress tolerance in a commercial cowpea variety.The transgenic lines displayed increased leaf area,thicker stem,nodule-rich denser root system,early flowering,higher pod production(~3.2-fold and~2.1-fold),and greater seed weight(10.3%and 6.0%).In contrast,transient suppression of VuNAC1/2 caused severe growth retardation and flower inhibition.The overexpressor lines showed remarkable tolerance to major yielddeclining terminal stresses,such as drought,salinity,heat,and cold,and recovered growth and seed production by boosting photosynthetic activity,water use efficiency,membrane integrity,Na^(+)/K^(+)homeostasis,and antioxidant activity.The comparative transcriptome study indicated consolidated activation of genes involved in chloroplast development,photosynthetic complexes,cell division and expansion,cell wall biogenesis,nutrient uptake and metabolism,stress response,abscisic acid,and auxin signaling.Unlike their orthologs,VuNAC1/2 direct synergistic transcriptional tuning of stress and developmental signaling to avoid unwanted trade-offs.Their overexpression governs the favorable interplay of photosynthesis and reactive oxygen species regulation to improve stress recovery,nutritional sufficiency,biomass,and production.This unconventional balance of strong stress tolerance and agronomic quality is useful for translational crop research and molecular breeding of pulses.

Design of functional biomaterials as substrates for corneal endothelium tissue engineering

Corneal endothelium defects are one of the leading causes of blindness worldwide.The actual treatment is transplantation,which requires the use of human cadaveric donors,but it faces several problems,such as global shortage of donors.Therefore,new alternatives are being developed and,among them,cell therapy has gained interest in the last years due to its promising results in tissue regeneration.Nevertheless,the direct administration of cells may sometimes have limited success due to the immune response,hence requiring the combination with extracellular mimicking materials.In this review,we present different methods to obtain corneal endothelial cells from diverse cell sources such as pluripotent or multipotent stem cells.Moreover,we discuss different substrates in order to allow a correct implantation as a cell sheet and to promote an enhanced cell behavior.For this reason,natural or synthetic matrixes that mimic the native environment have been developed.These matrixes have been optimized in terms of their physicochemical properties,such as stiffness,topography,composition and transparency.To further enhance the matrixes properties,these can be tuned by incorporating certain molecules that can be delivered in a sustained manner in order to enhance biological behavior.Finally,we elucidate future directions for corneal endothelial regeneration,such as 3D printing,in order to obtain patient-specific substrates.

Multiscattering-enhanced absorbance to enable the sensitive analysis of extremely diluted biological samples: Determination of oxidative potential in exhaled air

Direct determination of the oxidative potential in exhaled air(OPEA)as a biological indicator of the redox balance status in airways requires an extremely sensitive sensing approach to counterbalance the high dilution of the exhaled air matrix.In opposite to standard colorimetric assays based on Beer-Lambert Law,the use of simple multiscattering-enhanced absorbance(MEA)strategy results in an improved photonic sensing system.Based on this strategy and using the ferrous-xylenol orange assay,analytical performances allowing the detection of 3 pmol of H_(2)O_(2) could be obtained.The comparative analysis of photometric configurations–standard vs MEA–highlights the large absorbance gain obtained for tiny H_(2)O_(2) amounts–from 0 to 30 pmol–whereas similar sensing trends are observed at higher concentration range.The automated introduction of exhaled air sample into the reaction compartment via needle-impinger coupled with the MEA-based photonic cell enables ultrasensitive determination of OPEA in short time(<5 min).A pilot study conducted on healthy subjects(n=22)and chronic obstructive pulmonary disease(COPD)patients(n=23)volunteers shows a significant increase of the OPEA for COPD versus controls and strong negative correlation between OPEA and spirometry parameters(Tiffeneau index:FEV1/FVC)for ex-/non-smokers.Application perspectives to assess inflammatory episodes in obstructive lung diseases are thus made possible using this sensing approach.

Antibacterial approaches in tissue engineering using metal ions and nanoparticles:From mechanisms to applications

Bacterial infection of implanted scaffolds may have fatal consequences and,in combination with the emergence of multidrug bacterial resistance,the development of advanced antibacterial biomaterials and constructs is of great interest.Since decades ago,metals and their ions had been used to minimize bacterial infection risk and,more recently,metal-based nanomaterials,with improved antimicrobial properties,have been advocated as a novel and tunable alternative.A comprehensive review is provided on how metal ions and ion nanoparticles have the potential to decrease or eliminate unwanted bacteria.Antibacterial mechanisms such as oxidative stress induction,ion release and disruption of biomolecules are currently well accepted.However,the exact antimicrobial mechanisms of the discussed metal compounds remain poorly understood.The combination of different metal ions and surface decorations of nanoparticles will lead to synergistic effects and improved microbial killing,and allow to mitigate potential side effects to the host.Starting with a general overview of antibacterial mechanisms,we subsequently focus on specific metal ions such as silver,zinc,copper,iron and gold,and outline their distinct modes of action.Finally,we discuss the use of these metal ions and nanoparticles in tissue engineering to prevent implant failure.