An Evaluation Method of Human Gut Microbial Homeostasis by Testing Specific Fecal Microbiota

Research on microecology has been carried out with broad perspectives in recent decades,which has enabled a better understanding of the gut microbiota and its roles in human health and disease.It is of great significance to routinely acquire the status of the human gut microbiota;however,there is no method to evaluate the gut microbiome through small amounts of fecal microbes.In this study,we found ten predominant groups of gut bacteria that characterized the whole microbiome in the human gut from a large-sample Chinese cohort,constructed a real-time quantitative polymerase chain reaction(qPCR)method and developed a set of analytical approaches to detect these ten groups of predominant gut bacterial species with great maneuverability,efficiency,and quantitative features.Reference ranges for the ten predominant gut bacterial groups were established,and we found that the concentration and pairwise ratios of the ten predominant gut bacterial groups varied with age,indicating gut microbial dysbiosis.By comparing the detection results of liver cirrhosis(LC)patients with those of healthy control subjects,differences were then analyzed,and a classification model for the two groups was built by machine learning.Among the six established classification models,the model established by using the random forest algorithm achieved the highest area under the curve(AUC)value and sensitivity for predicting LC.This research enables easy,rapid,stable,and reliable testing and evaluation of the balance of the gut microbiota in the human body,which may contribute to clinical work.

H3K36 methyltransferase NSD1 regulates chondrocyte differentiation for skeletal development and fracture repair

Chondrocyte differentiation is a critical process for endochondral ossification,which is responsible for long bone development and fracture repair.Considerable progress has been made in understanding the transcriptional control of chondrocyte differentiation;however,epigenetic regulation of chondrocyte differentiation remains to be further studied.NSD1 is a H3K36(histone H3 at lysine 36)methyltransferase.Here,we showed that mice with Nsd1 deficiency in Prx1+mesenchymal progenitors but not in Col2+chondrocytes showed impaired skeletal growth and fracture healing accompanied by decreased chondrogenic differentiation.Via combined RNA sequencing(RNA-seq)and chromatin immunoprecipitation sequencing(ChIP-seq)analysis,we identified sex determining region Y box 9(Sox9),the key transcription factor of chondrogenic differentiation,as a functional target gene of NSD1.Mechanistically,NSD1 regulates Sox9 expression by modulating H3K36me1 and H3K36me2 levels in the Sox9 promoter region,constituting a novel epigenetic regulatory mechanism of chondrogenesis.Moreover,we found that NSD1 can directly activate the expression of hypoxia-inducible factor 1α(HIF1α),which plays a vital role in chondrogenic differentiation through its regulation of Sox9 expression.Collectively,the results of our study reveal crucial roles of NSD1 in regulating chondrogenic differentiation,skeletal growth,and fracture repair and expand our understanding of the function of epigenetic regulation in chondrogenesis and skeletal biology.

Engineering of a NIR-activable hydrogel-coated mesoporous bioactive glass scaffold with dual-mode parathyroid hormone derivative release property for angiogenesis and bone regeneration

Osteogenesis,osteoclastogenesis,and angiogenesis play crucial roles in bone regeneration.Parathyroid hormone(PTH),an FDA-approved drug with pro-osteogenic,pro-osteoclastogenic and proangiogenic capabilities,has been employed for clinical osteoporosis treatment through systemic intermittent administration.However,the successful application of PTH for local bone defect repair generally requires the incorporation and delivery by appropriate carriers.Though several scaffolds have been developed to deliver PTH,they suffer from the weaknesses such as uncontrollable PTH release,insufficient porous structure and low mechanical strength.Herein,a novel kind of NIR-activable scaffold(CBP/MBGS/PTHrP-2)with dual-mode PTHrP-2(a PTH derivative)release capability is developed to synergistically promote osteogenesis and angiogenesis for high-efficacy bone regeneration,which is fabricated by integrating the PTHrP-2-loaded hierarchically mesoporous bioactive glass(MBG)into the N-hydroxymethylacrylamide-modified,photothermal agent-doped,poly(N-isopropylacrylamide)-based thermosensitive hydrogels through assembly process.Upon on/off NIR irradiation,the thermoresponsive hydrogel gating undergoes a reversible phase transition to allow the precise control of on-demand pulsatile and long-term slow release of PTHrP-2 from MBG mesopores.Such NIR-activated dual-mode delivery of PTHrP-2 by this scaffold enables a well-maintained PTHrP-2 concentration at the bone defect sites to continually stimulate vascularization and promote osteoblasts to facilitate and accelerate bone remodeling.In vivo experiments confirm the significant improvement of bone reparative effect on critical-size femoral defects of rats.This work paves an avenue for the development of novel dual-mode delivery systems for effective bone regeneration.

Crimped nanofiber scaffold mimicking tendon-to-bone interface for fatty-infiltrated massive rotator cuff repair

Electrospun fibers,with proven ability to promote tissue regeneration,are widely being explored for rotator cuff repairing.However,without post treatment,the microstructure of the electrospun scaffold is vastly different from that of natural extracellular matrix(ECM).Moreover,during mechanical loading,the nanofibers slip that hampers the proliferation and differentiation of migrating stem cells.Here,electrospun nanofiber scaffolds,with crimped nanofibers and welded joints to biomimic the intricate natural microstructure of tendon-to-bone insertion,were prepared using poly(ester-urethane)urea and gelatin via electrospinning and double crosslinking by a multi-bonding network densification strategy.The crimped nanofiber scaffold(CNS)features bionic tensile stress and induces chondrogenic differentiation,laying credible basis for in vivo experimentation.After repairing a rabbit massive rotator cuff tear using a CNS for 3 months,the continuous translational tendon-to-bone interface was fully regenerated,and fatty infiltration was simultaneously inhibited.Instead of micro-CT,μCT was employed to visualize the integrity and intricateness of the three-dimensional microstructure of the CNS-induced-healed tendon-to-bone interface at an ultra-high resolution of less than 1μm.This study sheds light on the correlation between nanofiber post treatment and massive rotator cuff repair and provides a general strategy for crimped nanofiber preparation and tendon-to-bone interface imaging characterization.

Osteogenic and anti-tumor Cu and Mn-doped borosilicate nanoparticles for syncretic bone repair and chemodynamic therapy in bone tumor treatment

Critical bone defects caused by extensive excision of malignant bone tumor and the probability of tumor recurrence due to residual tumor cells make malignant bone tumor treatment a major clinical challenge.The present therapeutic strategy concentrates on implanting bone substitutes for defect filling but suffers from failures in both enhancing bone regeneration and inhibiting the growth of tumor cells.Herein,Cu and Mn-doped borosilicate nanoparticles(BSNs)were developed for syncretic bone repairing and anti-tumor treatment,which can enhance bone regeneration through the osteogenic effects of Cu^(2+) and Mn^(3+) ions and meanwhile induce tumor cells apoptosis through the hydroxyl radicals produced by the Fenton-like reactions of Cu^(2+) and Mn^(3+) ions.In vitro study showed that both osteogenic differentiation of BMSCs and angiogenesis of endothelial cells were promoted by BSNs,and consistently the critical bone defects of rats were efficiently repaired by BSNs through in vivo evaluation.Meanwhile,BSNs could generate hydroxyl radicals through Fenton-like reactions in the simulated tumor microenvironment,promote the generation of intracellular reactive oxygen species,and eventually induce tumor cell apoptosis.Besides,subcutaneous tumors of mice were effectively inhibited by BSNs without causing toxic side effects to normal tissues and organs.Altogether,Cu and Mn-doped BSNs developed in this work performed dual functions of enhancing osteogenesis and angiogenesis for bone regeneration,and inhibiting tumor growth for chemodynamic therapy,thus holding a great potential for syncretic bone repairing and anti-tumor therapy.