Bioactive biodegradable polycitrate nanoclusters enhances the myoblast differentiation and in vivo skeletal muscle regeneration via p38 MAPK signaling pathway

Complete skeletal muscle repair and regeneration due to severe large injury or disease is still a challenge.Biochemical cues are critical to control myoblast cell function and can be utilized to develop smart biomaterials for skeletal muscle engineering.Citric acid-based biodegradable polymers have received much attention on tissue engineering,however,their regulation on myoblast cell differentiation and mechanism was few investigated.Here,we find that citrate-based polycitrate-polyethylene glycol-polyethylenimine(POCG-PEI600)nanoclusters can significantly enhance the in vitro myoblast proliferation by probably reinforcing the mitochondrial number,promote the myotube formation and full-thickness skeletal muscle regeneration in vivo by activating the myogenic biomarker genes expression of Myod and Mhc.POCG-PEI600 nanoclusters could also promote the phosphorylation of p38 in MAP kinases(MAPK)signaling pathway,which led to the promotion of the myoblast differentiation.The in vivo skeletal muscle loss rat model also confirmed that POCG-PEI600 nanoclusters could significantly improve the angiogenesis,myofibers formation and complete skeletal muscle regeneration.POCG-PEI600 nanocluster could be also biodegraded into small molecules and eliminated in vivo,suggesting their high biocompatibility and biosafety.This study could provide a bioactive biomaterial-based strategy to repair and regenerate skeletal muscle tissue.

Corrigendum to“Injectable muscle-adhesive antioxidant conductive photothermal bioactive nanomatrix for efficiently promoting full-thickness skeletal muscle regeneration”[Bioact Mater,6(2021)1605-1617]

The authors regret that the fluorescent image for FPC-7day in Figure 5A was reproduced incorrectly,although which did not affect the conclusion of this work.

Customizable Ligand Exchange for Tailored Surface Property of Noble Metal Nanocrystals

It is highly desirable,while still challenging,to obtain noble metal nanocrystals with custom capping ligands,because their colloidal synthesis relies on specific capping ligands for the shape control while conventional ligand exchange processes suffer from“the strong replaces the weak”limitation,which greatly hinders their applications.Herein,we report a general and effective ligand exchange approach that can replace the native capping ligands of noble metal nanocrystals with virtually any type of ligands,producing flexibly tailored surface properties.The key is to use diethylamine with conveniently switchable binding affinity to the metal surface as an intermediate ligand.As a strong ligand,it in its original form can effectively remove the native ligands;while protonated,it loses its binding affinity and facilitates the adsorption of new ligands,especially weak ones,onto the metal surface.By this means,the irreversible order in the conventional ligand exchange processes could be overcome.The efficacy of the strategy is demonstrated by mutual exchange of the capping ligands among cetyltrimethylammonium,citrate,polyvinylpyrrolidone,and oleylamine.This novel strategy significantly expands our ability to manipulate the surface property of noble metal nanocrystals and extends their applicability to a wide range of fields,particularly biomedical applications.

Injectable muscle-adhesive antioxidant conductive photothermal bioactive nanomatrix for efficiently promoting full-thickness skeletal muscle regeneration

The completed skeletal muscle regeneration resulted from severe injury and muscle-related disease is still a challenge.Here,we developed an injectable muscle-adhesive antioxidant conductive bioactive photothermo-responsive nanomatrix for regulating the myogenic differentiation and promoting the skeletal muscle regeneration in vivo.The multifunctional nanomatrix was composed of polypyrrole@polydopamine(PPy@PDA,342±5.6 nm)nanoparticles-crosslinked Pluronic F-127(F127)-polycitrate matrix(FPCP).The FPCP nanomatrix demonstrated inherent multifunctional properties including excellent photothermo-responsive and shear-thinning behavior,muscle-adhesive feature,injectable ability,electronic conductivity(0.48±0.03 S/m)and antioxidant activity and photothermal function.The FPCP nanomatrix displayed better photothermal performance with near-infrared irradiation,which could provide the photo-controlled release of protein(91%±2.6%of BSA was released after irradiated 3 times).Additionally,FPCP nanomatrix could significantly enhance the cell proliferation and myogenic differentiation of mouse myoblast cells(C2C12)by promoting the expressions of myogenic genes(MyoD and MyoG)and myosin heavy chain(MHC)protein with negligible cytotoxicity.Based on the multifunctional properties,FPCP nanomatrix efficiently promoted the full-thickness skeletal muscle repair and regeneration in vivo,through stimulating the angiogenesis and myotube formation.This study firstly indicated the vital role of multifunctional PPy@PDA nanoparticles in regulating myogenic differentiation and skeletal muscle regeneration.This work also suggests that rational design of bioactive matrix with multifunctional feature would greatly enhance the development of regenerative medicine.

Heterozygous CARD9 mutation favors the development of allergic bronchopulmonary aspergillosis

Background:Previous research demonstrated that a homozygous mutation of g.136372044G>A(S12N)in caspase recruitment domain family member 9(CARD9)is critical for producing Aspergillus fumigatus-induced(Af-induced)T helper 2(T_(H)2)-mediated responses in allergic bronchopulmonary aspergillosis(ABPA).However,it remains unclear whether the CARD9^(S12N)mutation,especially the heterozygous occurrence,predisposes the host to ABPA.Methods:A total of 61 ABPA patients and 264 controls(including 156 healthy controls and 108 asthma patients)were recruited for sequencing the CARD9 locus to clarify whether patients with this heterozygous single-nucleotide polymorphisms are predisposed to the development of ABPA.A series of in vivo and in vitro experiments,such as quantitative real-time polymerase chain reaction,flow cytometry,and RNA isolation and quantification,were used to illuminate the involved mechanism of the disease.Results:The presence of the p.S12N mutation was associated with a significant risk of ABPA in ABPA patients when compared with healthy controls and asthma patients,regardless of Aspergillus sensitivity.Relative to healthy controls without relevant allergies,the mutation of p.S12N was associated with a significant risk of ABPA(OR:2.69 and 4.17 for GA and AA genotypes,P=0.003 and 0.029,respectively).Compared with patients with asthma,ABPA patients had a significantly higher heterozygous mutation(GA genotype),indicating that p.S12N might be a significant ABPA-susceptibility locus(aspergillus sensitized asthma:OR:3.02,P=0.009;aspergillus unsensitized asthma:OR:2.94,P=0.005).The mutant allele was preferentially expressed in ABPA patients with heterozygous CARD9^(S12N),which contributes to its functional alterations to facilitate Af-induced T_(H)2-mediated ABPA development.In terms of mechanism,Card9 wild-type(Card9^(WT))expression levels decreased significantly due to Af-induced decay of its messenger RNA compared to the heterozygous Card9 S12N.In addition,ABPA patients with heterozygous CARD9^(S12N)had increased Af-induced interleukin-5 production.Conclusion:Our study provides the genetic evidence showing that the heterozygous mutation of CARD9^(S12N),followed by allele expression imbalance of CARD9^(S12N),facilitates the development of ABPA.

A patient with DAX1 mutation presenting with elevated testosterone in early infancy

Dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome 1 (DAX1) deficiency is a rare disorder presents X-Linked adrenal hypoplasia congenital,impaired sexual development and infertility.Mutational gene of DAX1 was identified as NROB1 [1] which expresses in adrenal gland and hypothalamic-pituitary-gonad axis,restrains progenitor stem cells from differentiating into steroidogenic cells prematurely.Therefore,DAX1 deficiency usually manifests primary adrenal insufficiency and hypogonadotropic hypogonadism.However,we observed a patient whose testosterone elevated in early infancy.

Hybrid Bioelastomer Reinforced by Ultrathin Nanowires of Lanthanide Hydroxycarbonates for Promising Biomedical Applications

Hybrids composed of biocompatible polymers reinforced with inorganic nanomaterials are useful for many biomedical applications including implantation and tissue regeneration and engineering.In this work,we report a new type of hybrid prepared by doping ultrathin nanowires of lanthanide hydroxycarbonates into classical biocompatible poly(citrates-siloxane).The doping of the inorganic nanowires imparts the hybrids with excellent miscibility with the polymeric matrix,producing hybrids with high elasticity and high tensile strength.The hybrids containing Eu(III)and Gd(III)display their respective luminescence and magnetic properties and thus,offer opportunities to monitor the fate of such hybrids when used in vivo.Insignificant degradation and excellent biocompatibility of these hybrids have also been demonstrated.Together,these favorable traits portend useful applications of the newly developed hybrid elastomers.