Acidosis and Deafness in Patients with Recessive Mutations in FOXI1

Maintenance of the composition of inner ear fluid and regulation of electrolytes and acid-base homeostasis in the collecting duct system of the kidney require an overlapping set of membrane transport proteins regulated by the forkhead transcription factor FOXI1. In two unrelated consanguineous families, we identified three patients with novel homozygous missense mutations in FOXI1 (p.L146F and p.R213P) predicted to affect the highly conserved DNA binding domain. Patients presented with early-onset sensorineural deafness and distal renal tubular acidosis. In cultured cells, the mutations reduced the DNA binding affinity of FOXI1, which hence, failed to adequately activate genes crucial for normal inner ear function and acidbase regulation in the kidney. A substantial proportion of patients with a clinical diagnosis of inherited distal renal tubular acidosis has no identified causative mutations in currently known disease genes. Our data suggest that recessive mutations in FOXI1 can explain the disease in a subset of these patients

Colocalization of the (Pro)renin receptor/Atp6ap2 with H+-AT pases in mouse kidney but prorenin does not acutely regulate intercalated cell H+-ATPase activity

The (Pro)renin receptor (P)RR/Atp6ap2 is a cell surface protein capable of binding and nonproteolytically activate prorenin. Additionally, (P)RR is associated with H+-ATPases and alternative functions in H+-ATPase regulation as well as inWnt signalling have been reported. Kidneys express very high levels of H+-ATPases which are involved in multiple functions such as endocytosis, membrane protein recycling as well as urinary acidification, bicarbonate reabsorption, and salt absorption. Here, we wanted to localize the (P)RR/Atp6ap2 along the murine nephron, exmaine whether the (P)RR/Atp6ap2 is co

Silver nanoparticles promote the emergence of heterogeneic human neutrophil sub-populations

Neutrophil surveillance is central to nanoparticle clearance. Silver nanoparticles (AgNP) have numerous uses, however conflicting evidence exists as to their impact on neutrophils and whether they trigger damaging inflammation. Neutrophil’s importance in innate defence and regulating immune networks mean it’s essential we understand AgNP’s impact on neutrophil function. Human neutrophil viability following AgNP or Ag Bulk treatment was analysed by flow cytometry and AnV/PI staining. Whilst AgNP exposure did not increase the total number of apoptotic neutrophils, the number of late apoptotic neutrophils was increased, suggesting AgNP increase transit through apoptosis. Mature (CD16bright/CD62Lbright), immature (CD16dim/CD62Lbright) and apoptotic (CD16dim/CD62Ldim) neutrophil populations were evident within isolated neutrophil preparations. AgNP exposure significantly reduced CD62L staining of CD16bright/CD62Lbright neutrophils, and increased CD16 staining of CD16dim/CD62Lbright populations, suggesting AgNPs trigger neutrophil activation and maturation, respectively. AgNP exposure dramatically increased IL-8, yet not classical pro-inflammatory cytokine release, suggesting AgNP triggers neutrophil activation, without pro-inflammation or damaging, necrotic cell death. For the first time, we show AgNPs differentially affect distinct sub-populations of circulating human neutrophils; activating mature neutrophils with the emergence of CD16bright/CD62Ldim neutrophils. This may stimulate particle clearance without harmful inflammation, challenging previous assumptions that silver nanomaterials induce neutrophil toxicity and damaging inflammatory responses

Up-regulation of FGF23 release by aldosterone

The fibroblast growth factor (FGF23) plasma level is high in cardiac and renal failure and is associated with poor clinical prognosis of these disorders. Both diseases are paralleled by hyperaldosteronism. Excessive FGF23 levels and hyperaldosteronism are further observed in Klotho-deficient mice. The present study explored a putative aldosterone sensitivity of Fgf23 transcription and secretion the putative involvement of the aldosterone sensitive serum & glucocorticoid inducible kinase SGK1, SGK1 sensitive transcription factor NFκB and store operated Ca(2+) entry (SOCE). Serum FGF23 levels were determined by ELISA in mice following sham treatment or exposure to deoxycorticosterone acetate (DOCA) or salt depletion. In osteoblastic UMR106 cells transcript levels were quantified by qRT-PCR, cytosolic Ca(2+) concentration utilizing Fura-2-fluorescence, and SOCE from Ca(2+) entry following store depletion by thapsigargin. As a result, DOCA treatment and salt depletion of mice elevated the serum C-terminal FGF23 concentration. In UMR106 cells aldosterone enhanced and spironolactone decreased SOCE. Aldosterone further increased Fgf23 transcript levels in UMR106 cells, an effect reversed by mineralocorticoid receptor blockers spironolactone and eplerenone, SGK1 inhibitor EMD638683, NFκB-inhibitor withaferin A, and Ca(2+) channel blocker YM58483. In conclusion, Fgf23 expression is up-regulated by aldosterone, an effect sensitive to SGK1, NFκB and store-operated Ca(2+) entry

NFκB-sensitive Orai1 expression in the regulation of FGF23 release

Fibroblast growth factor (FGF23) plasma levels are elevated in cardiac and renal failure and correlate with poor clinical prognosis of those disorders. Both disorders are associated with inflammation and activation of the inflammatory transcription factor NFκB. An excessive FGF23 level is further observed in Klotho-deficient mice. The present study explored a putative sensitivity of FGF23 expression to transcription factor NFκB, which is known to upregulate Orai1, the Ca(2+) channel accomplishing store-operated Ca(2+) entry (SOCE). In osteoblastic cells (UMR106) and immortalized primary periosteal (IPO) cells, protein abundance was determined by Western blotting, and in UMR106 cells, transcript levels were quantified by RT-PCR, cytosolic Ca(2+) activity utilizing Fura-2-fluorescence, and SOCE from Ca(2+) entry following store depletion by thapsigargin. As a result, UMR106 and IPO cells expressed Ca(2+) channel Orai1. SOCE was lowered by NFκB inhibitor wogonin as well as by Orai1 inhibitors 2-APB and YM58483. UMR106 cell Fgf23 transcripts were increased by stimulation of SOCE and Ca(2+) ionophore ionomycin and decreased by Orai inhibitors 2-APB, YM58483 and SK&F96365, by Orai1 silencing, as well as by NFκB inhibitors wogonin, withaferin A, and CAS 545380-34-5. In conclusion, Fgf23 expression is upregulated by stimulation of NFκB-sensitive, store-operated Ca(2+) entry. KEY MESSAGES Osteoblast UMR106 and IPO cells express Ca(2+) channel Orai1. Osteoblast store-operated Ca(2+) entry is accomplished by NFκB-sensitive Orai1. Osteoblast Fgf23 transcription is upregulated by increase in the cytosolic Ca(2+) activity. Fgf23 transcription is decreased by Orai inhibitors and Orai1 silencing. Fgf23 transcription is lowered by NFκB inhibitors

Dynamic Mechanical Analysis and High Strain-Rate Energy Absorption Characteristics of Vertically Aligned Carbon Nanotube Reinforced Woven Fiber-Glass Composites

The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and polyurethane (PU) resin systems (FG/PE/VACNT and FG/PU/VACNT) are investigated and compared with the baseline materials, FG/PE and FG/PU (i.e., without VACNT). A Dynamic Mechanical Analyzer (DMA) was used for obtaining the mechanical properties. It was found that FG/PE/VACNT exhibited a significantly lower flexural stiffness at ambient temperature along with higher damping loss factor over the investigated temperature range compared to the baseline material FG/PE. For FG/PU/VACNT, a significant increase in flexural stiffness at ambient temperature along with a lower damping loss factor was observed with respect to the baseline material FG/PU. A Split Hopkinson Pressure Bar (SHPB) was used to evaluate the energy absorption and strength of specimens under high strain-rate compression loading. It was found that the specific energy absorption increased with VACNT layers embedded in both FG/PE and FG/PU. The compressive strength also increased with the addition of VACNT forest layers in FG/PU; however, it did not show an improvement for FG/PE

Microscale 3D Printing of Nanotwinned Copper

Nanotwinned (nt)‐metals exhibit superior mechanical and electrical properties compared to their coarse‐grained and nanograined counterparts. nt‐metals in film and bulk forms are obtained using physical and chemical processes including pulsed electrodeposition (PED), plastic deformation, recrystallization, phase transformation, and sputter deposition. However, currently, there is no process for 3D printing (additive manufacturing) of nt‐metals. Microscale 3D printing of nt‐Cu is demonstrated with high density of coherent twin boundaries using a new room temperature process based on localized PED (L‐PED). The 3D printed nt‐Cu is fully dense, with low to none impurities, and low microstructural defects, and without obvious interface between printed layers, which overall result in good mechanical and electrical properties, without any postprocessing steps. The L‐PED process enables direct 3D printing of layer‐by‐layer and complex 3D microscale nt‐Cu structures, which may find applications for fabrication of metamaterials, sensors, plasmonics, and micro/nanoelectromechanical systems

Localized Pulsed Electrodeposition Process for Three-Dimensional Printing of Nanotwinned Metallic Nanostructures

Nanotwinned-metals (nt-metals) offer superior mechanical (high ductility and strength) and electrical (low electromigration) properties compared to their nanocrystalline (nc) counterparts. These properties are advantageous in particular for applications in nanoscale devices. However, fabrication of nt-metals has been limited to films (two-dimensional) or template-based (one-dimensional) geometries, using various chemical and physical processes. In this Letter, we demonstrate the ambient environment localized pulsed electrodeposition process for direct printing of three-dimensional (3D) freestanding nanotwinned-Copper (nt-Cu) nanostructures. 3D nt-Cu structures were additively manufactured using pulsed electrodeposition at the tip of an electrolyte-containing nozzle. Focused ion beam (FIB) and transmission electron microscopy (TEM) analysis revealed that the printed metal was fully dense, and was mostly devoid of impurities and microstructural defects. FIB and TEM images also revealed nanocrystalline-nanotwinned-microstructure (nc-nt-microstructure), and confirmed the formation of coherent twin boundaries in the 3D-printed Cu. Mechanical properties of the 3D-printed nc-nt-Cu were characterized by direct printing (FIB-less) of micropillars for in situ SEM microcompression experiments. The 3D-printed nc-nt-Cu exhibited a flow stress of over 960 MPa, among the highest ever reported, which is remarkable for a 3D-printed material. The microstructure and mechanical properties of the nc-nt-Cu were compared to those of nc-Cu printed using the same process under direct current (DC) voltage