Zn/Sr dual ions-collagen co-assembly hydroxyapatite enhances bone regeneration through procedural osteo-immunomodulation and osteogenesis

The immune microenvironment induced by biomaterials played vital roles in bone regeneration.Hydroxyapatite(HA)and its ion-substituted derivates represent a large class of core inorganic materials for bone tissue engineering.Although ion substitution was proved to be a potent way to grant HA more biological functions,few studies focused on the immunomodulatory properties of ion-doped HA.Herein,to explore the potential osteoimmunomodulatory effects of ion-doped HA,zinc and strontium co-assembled into HA through a collagen template biomimetic way(ZnSr-Col-HA)was successfully achieved.It was found that ZnSr-Col-HA could induce a favorable osteo-immune microenvironment by stimulating macrophages.Furthermore,ZnSr-Col-HA demonstrated a procedural promoting effect on osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)in vitro.Specifically,the osteo-immune microenvironment acted as a dominant factor in promoting osteogenic gene expressions at the early stage through OSM signal pathway.Whereas the direct stimulating effects on BMSCs by Zn^(2+)/Sr^(2+) were more effectively at the later stage with Nfatc1/Maf and Wnt signals activated.In vivo study confirmed strong promoting effects of ZnSr-Col-HA on critical-sized cranial defect repair.The current study indicated that such a combined biomaterial design philosophy of dual ion-doping and biomimetic molecular co-assembly to endow HA applicable osteoimmunomodulatory characteristics might bring up a new cutting-edge concept for bone regeneration study.

Micropatterned composite membrane guides oriented cell growth and vascularization for accelerating wound healing

Skin defect is common in daily life,but repairing large skin defects remains a challenge.Using biomaterials to deliver biochemical or physical factors to promote skin tissue regeneration is of great significance for accelerating wound healing.Specific surface micropatterns on biomaterials could affect cell behavior and tissue regeneration.However,few studies have focused on the construction of wound healing biomaterials with surface micropatterns and their role in skin tissue regeneration.In the present study,gelatin-polycaprolactone/silk fibroin composite membranes with different micropatterns were fabricated by photolithography,including line,grid and plane micropatterns.In vitro cell experiments demonstrated that the line micropattern on the composite membrane could guide cell-oriented growth,and more importantly,promote the expression of angiogenesis-related markers andα-smooth muscle actin(α-SMA)at both gene level and protein level.In the rat full-thickness skin defect model,the composite membrane with line micropatterns increasedα-SMA production and neovascularization in wounds,leading to accelerated wound contraction and healing.The current study not only suggests that composite membranes with specific micropatterns can be promising wound repair materials but also provides new insights into the importance of biomaterial surface topology for tissue regeneration.

The HOXC10/NOD1/ERK axis drives osteolytic bone metastasis of pan-KRAS-mutant lung cancer

While KRAS mutation is the leading cause of low survival rates in lung cancer bone metastasis patients,effective treatments are still lacking.Here,we identified homeobox C10(HOXC10)as a lynchpin in pan-KRAS-mutant lung cancer bone metastasis.

Injectable bone cement with magnesium-containing microspheres enhances osteogenesis via anti-inflammatory immunoregulation

Injectable bone cement is especially useful in minimally invasive surgeries to repair small and irregular bone defects.Amongst different kinds of injectable bone cements,bioactive calcium phosphate bone cement(CPC)has been widely studied due to its biological activity.However,its dense structure and poor biodegradability prevent the ingrowth of living tissue,which leads to undesirable bone regeneration and clinical translation.To address this issue,we prepared bone cement based on Magnesium-containing microspheres(MMSs)that can not only be cured into a 3D porous scaffold but also have controllable biodegradability that continuously provides space for desired tissue ingrowth.Interestingly,magnesium ions released from MMSs cement(MMSC)trigger positive immunomodulation via upregulation of the anti-inflammatory genes IL-10 and M2 macrophage polarization with increased expression of CD206,which is beneficial to osteogenesis.Moreover,the physicochemical properties of MMSC,including heat release,rheology and setting time,can be tuned to meet the requirements of injectable bone cement for clinical application.Using a rat model,we have demonstrated that MMSC promoted osteogenesis via mediation of tissue ingrowth and anti-inflammatory immunomodulation.The study provides a paradigm for the design and preparation of injectable bone cements with 3D porous structures,biodegradability and anti-inflammatory immunoregulation to efficiently promote osteogenesis.

Si-doping bone composite based on protein template- mediated assembly for enhancing bone regeneration

Bio-inspired hybrid materials that contain organic and inorganic networks interpenetration at the molecular level have been a particular focus of interest on designing novel nanoscale composites. Here we firstly synthesized a series of hybrid bone composites, silicon-hydroxyapatites/silk fibroin/collagen, based on a specific molecular assembled strategy. Results of material characterization confirmed that silicate had been successfully doped into nano-hydroxyapatite lattice. In vitro evaluation at the cellular level clearly showed that these Si-doped composites were capable of promoting the adhesion and proliferation of rat mesenchymal stem cells （rMSCs）, extremely enhancing osteoblastic differentiation of rMSCs compared with silicon-free composite. More interestingly, we found there was a critical point of silicon content in the composition on regulating multiple cell behaviors. In vivo animal evaluation further demonstrated that Si-doped composites enabled to significantly improve the repair of cranial bone defect. Consequently, our current work not only suggests fabricating a potential bone repair materials by integrating element-doping and molecular assembled strategy in one system, but also paves a new way for constructing multi-functional composite materials in the future.

Albumin-assembled copper-bismuth bimetallic sulfide bioactive nanosphere as an amplifier of oxidative stress for enhanced radio-chemodynamic combination therapy

The tumor microenvironment with overexpressed hydrogen peroxide(H_(2)O_(2))and reinforced antioxidative system(glutathione,GSH)becomes a double-edged sword for the accessibility of nano-therapy.Since reactive oxygen species(ROS)are easily quenched by the developed antioxidative network,ROS-based treatments such as chemodynamic therapy(CDT)and radiotherapy(RT)for killing cancer cells are severely attenuated.To overcome such limitations,a bioactive nanosphere system is developed to regulate intracellular oxidative stress for enhanced radio-chemodynamic combination therapy by using bovine serum albumin(BSA)based bioactive nanospheres that are BSA assembled with in situ generated copper-bismuth sulfide nanodots and diallyl trisulfide(DATS).The copper-bismuth sulfide nanodots react with H_(2)O_(2)to produce·OH and release Cu^(2+).Then,the Cu^(2+)further depletes GSH to generate Cu^(+)for more·OH generation in the way of Fenton-like reaction.Such a cascade reaction can initiate·OH generation and GSH consumption to realize CDT.The elevation of ROS triggered by the DATS from BBCD nanospheres further augments the breaking of redox balance for the increased oxidative stress in 4T1 cells.With the sensitization of increased oxidative stress and high Z element Bi,an enhanced radio-chemodynamic combination therapy is achieved.The current work provides an enhanced radio-chemodynamic combination treatment for the majority of solid tumors by using the co-assembled bioactive nanospheres as an amplifier of oxidative stress.

SARS-CoV-2 Omicron Variant is Expected to Retain Most of the Spike Protein Specific Dominant T-Cell Epitopes Presented by COVID-19 Vaccines—Worldwide,2021

Summary What is already known about this topic?The newly emerged variant of Omicron,which carries many of the mutations found in other variants of concern(VOCs),as well as a great number of new mutations that may enhance its immune escape,has spread rapidly around the world.This has raised public concern about the effectiveness of the current coronavirus disease 2019(COVID-19)vaccine.What is added by this report?In this study,different bioinformatic softwares were applied to predict the dominant Omicron spike(S)protein cytotoxic T lymphocyte(CTL)and T helper(Th)epitopes in representative world population and Chinese population.Compared to the original severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)S protein,limited mutations were identified within the dominant CTL and Th epitopes in Omicron variant.What are the implications for public health practice?The results of this study suggested that the current COVID-19 vaccine-induced T-cell immunity may still provide significant protection against Omicron variant infection in fully vaccinated individuals.