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Bone defect is a serious orthopedic disease which has been studied for a long time. Alternative degradable biomaterials are required for bone repairing and regeneration to address the limitation of autogenous bone. β-tricalcium phosphate (β-TCP) is an alternative material with good cytocompatibility and has been used in bone defect treatment. However, whether β-TCP contributes to osteogenesis of bone marrow stem cells (BMSCs) through N6-methyladenosine (m6A) modification remains unknown. To address this issue, we verified the effects of β-TCP on osteogenesis of BMSCs. We also studied the expression of m6A-related enzymes in BMSCs after β-TCP treatment. Furthermore, the m6A level and stability of Runt-related transcription factor 2 (RUNX2) mRNA were investigated after β-TCP treatment. Finally, rat calvarial defect models were performed to detect expression level of osteogenic factors and m6A-related enzymes after the stimulation of three-dimension (3D)-printed β-TCP scaffolds. We found that β-TCP showed good biocompatibility and was osteoinductive. Meanwhile, methyltransferase-like 3 (METTL3) increased, causing the elevation of m6A level of RUNX2, results in stabler RUNX2 mRNA level. At last, based on the animal experiments, we demonstrated that the increase of RUNX2 and METTL3 levels was induced by β-TCP. These findings suggest that METTL3 increases the m6A level of RUNX2 mRNA after β-TCP induction, contributing to its stability, and the results in vivo also confirmed the osteogenic and bone-repair properties of β-TCP.

Current treatments of osteoarthritis, such as oral medication and intra-articular injections, only provided temporary relief from pain and achieved limited advance in inhibiting progression. The development of new treatments is hindered by the complicated and unclear pathological mechanisms. Oxidative stress and immune inflammation are believed to be the important factors in the induction and progression of osteoarthritis. Herein, this work presents a bioactive material strategy to treat osteoarthritis, based on the FPSOH matrixgel with robust anti-inflammatory activity through inhibiting the oxidative stress and nuclear factor kappa B signaling, preventing the metalloproteinase, as well as inducing M2 polarization of macrophage, thereby providing immune regulation of synovial macrophages and suppressing the progression of synovitis and osteoarthritis.

Background Although biomedical implants have been widely used in orthopedic treatments, two major clinical challenges remained to be solved, one is the bacterial infection resulting in biofilm formation, and the other is aseptic loosening during implantation due to over-activated osteoclastogenesis. These factors can cause many clinical issues and even lead to implant failure. Thus, it is necessary to endow implants with antibiofilm and aseptic loosening-prevention properties, to facilitate the integration between implants and bone tissues for successful implantation. To achieve this goal, this study aimed to develop a biocompatible titanium alloy with antibiofilm and anti-aseptic loosening dual function by utilizing gallium (Ga) as a component. Methods A series of Ti-Ga alloys were prepared. We examined the Ga content, Ga distribution, hardness, biocompatibility, and anti-biofilm performance in vitro and in vivo. We also explored how Ga3+ ions inhibited the biofilm formation of S. aureus and E. coli and osteoclast differentiation. Results The alloy exhibited outstanding antibiofilm properties against both S. aureus and E. coli in vitro and decent antibiofilm performance against S. aureus in vivo. The proteomics results demonstrated that Ga3+ ions could disturb the bacterial Fe metabolism of both S. aureus and E. coli, inhibiting bacterial biofilm formation. In addition, Ti-Ga alloys could inhibit receptor activator of nuclear factor-κB ligand (RANKL)-dependent osteoclast differentiation and function by targeting iron metabolism, then suppressing the activation of the NF-κB signaling pathway, thus, showing their potential to prevent aseptic loosening. Conclusions This study provides an advanced Ti-Ga alloy that can be used as a promising orthopedic implant raw material for various clinical scenarios. This work also revealed that iron metabolism is the common target of Ga3+ ions to inhibit biofilm formation and osteoclast differentiation.

Background Lipped or elevated acetabular liners are to improve posterior stability and are widely used in hip arthroplasty. However, concerns of increasing impingement exist when using such liners and optimal orientation of the elevated rim remains unknown. We aimed to identify the impact of lipped liner on the range of motion (ROM) before impingement and propose its optimal orientation. Methods An isochoric three-dimensional model of a general hip-replacement prosthesis was generated, and flex-extension, add-abduction and axial rotation were simulated on a computer. The maximum ROM of the hip was measured before the neck impinged on the liner. Different combinations of acetabular anteversion angles ranging from 5 to 30 degrees, and lipped liner orientations from posterior to anterior were tested. Results When acetabular anteversion was 10 or 15 degrees, placing the lip of the liner in the posterosuperior of the acetabulum allowed satisfactory ROM in all directions. When acetabular anteversion was 20 degrees, extension and external rotation were restricted. Adjusting the lip to the superior restored satisfactory ROM. When acetabular anteversion was 25 degrees, only placing the lip into the anterosuperior could increase extension and external rotation to maintain satisfactory ROM. Conclusions This study showed that optimal lipped liner orientation should depend on acetabular anteversion. When acetabular anteversion was smaller than 20 degrees, placing lip in the posterior allowed an optimally ROM. When acetabular anteversion was greater than 20 degrees, adjusting lip to the anterior allowed a comprehensive larger ROM to avoid early impingement.

Tendinopathy is a common disease influencing life quality and tendon function of patients, especially in the elderly and athletes. Inflammation is an important pathologic process of tendinopathy. Hypoxia inducible factor-1 alpha (HIF-1α) participates actively in inflammatory process. However, little is known about the role of HIF-1α in tendinopathy. To address this issue, we verified the expression level of HIF-1α in tendinopathy in vivo and in vitro. Furthermore, the severity of tendinopathy in vivo and in vitro was assessed after HIF-1α inhibition. At the same time, inflammatory signaling cascades were evaluated. The expression level of HIF-1α increased in tendinopathy in vivo and in vitro. The migration and proliferation of tendon cells (TDCs) were reduced after HIF-1α inhibition. In the meantime, HIF-1α inhibition alleviated the severity of tendinopathy and promoted tendon repairing. We also found that HIF-1α inhibition reduced the phosphorylation levels of p65 in NF-κB signaling pathway and the phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and Jun N-terminal kinase (JNK) in MAPK signaling pathway. These findings suggest that HIF-1α increases in tendinopathy in vivo and vitro, and HIF-1α inhibition can suppress the severity of tendinopathy by blocking NF-κB and MAPK signaling pathways.

Aberrant expression or genomic mutations of microRNA have been reported to be associated with a variety of human diseases. This study is aimed to analyze the association between genetic variations of miRNA and schizophrenia or bipolar disorder. We performed case-control studies for ten SNPs in a total sample of 1584 Chinese subjects. All these ten SNPs are on or near mature microRNAs which are expressed in the brain. To illustrate the function of miR-27a, we constructed a miR-27a knockout (KO) astrocytoma cell line U-251MG. By comparing the differentially expressed genes in wild-type and KO U-251MG, we determined several candidate target genes of miR-27a and then verified ICAM-1 as a target gene of miR-27a. We identified the association between the T/C polymorphism at rs895819 and bipolar disorder. Ectopic expression of miR-27a in NPCs showed that the T to C mutation at rs895819 reduced the suppressive effects of miR-27a on the expression of its target genes. Further studies revealed that the T/C polymorphism on miR-27a led to differential expression of mature and precursor miR-27a without affecting the expression of primary miR-27a. Our study highlighted the importance of miR-27a and its polymorphism at rs895819 in bipolar disorder.

The aberrant expression or genomic mutations of microRNA are associated with several human diseases. This study analyzes the relationship between genetic variations of miRNA and schizophrenia or bipolar disorder. We performed case-control studies for ten SNPs in a total sample of 1584 subjects. All these ten SNPs were on or near mature microRNAs. We identified the association between bipolar disorder and the T/C polymorphism at rs895819. To illustrate the function of miR-27a, we constructed several miR-27a knockout (KO) cell lines, determined candidates of miR-27a, and then verified NCAM1 as a target gene of miR-27a. Further studies revealed that the T/C polymorphism on miR-27a led to the differential expression of mature and precursor miR-27a without affecting the expression of primary miR-27a. Furthermore, the C mutation on pre-miR-27a suppresses cell migration and dopamine expression levels. Our study highlights the importance of miR-27a and its polymorphism at rs895819 in bipolar disorder.

Mechanical loading enhances the progression of osteoarthritis. However, its molecular mechanisms have not been established. The aim of this review was to summarize the probable mechanisms of mechanical load-induced osteoarthritis. A comprehensive search strategy was used to search PubMed and EMBASE databases (from the 15th of January 2015 to the 20th of October 2020). Search terms included “osteoarthritis”, “mechanical load”, and “mechanism”. Abnormal mechanical loading activates the interleukin-1β, tumour necrosis factor-α, nuclear factor kappa-B, Wnt, transforming growth factor-β, microRNAs pathways, and the oxidative stress pathway. These pathways induce the pathological progression of osteoarthritis. Mechanical stress signal receptors such as integrin, ion channel receptors, hydrogen peroxide-inducible clone-5, Gremlin-1, and transient receptor potential channel 4 are present in the articular cartilages. This review highlights the molecular mechanisms of mechanical loading in inducing chondrocyte apoptosis and extracellular matrix degradation. These mechanisms provide potential targets for osteoarthritis prevention and treatment.

Fluorogenic labeling enables imaging cellular molecules of interest with minimal background. This process is accompanied with the notable increase of the quantum yield of fluorophore, thus minimizing the background signals from unactivated profluorophores. Herein, the development of a highly efficient and bioorthogonal nitroso‐based Diels–Alder fluorogenic reaction is presented and its usefulness is validated as effective and controllable in fluorescent probes and live‐cell labeling strategies for dynamic cellular imaging. It is demonstrated that nitroso‐based cycloaddition is an efficient fluorogenic labeling tool through experiments of further UV‐activatable fluorescent labeling on proteins and live cells. The ability of tuning the fluorescence of labeled proteins by UV‐irradiation enables selective activation of proteins of interest in a particular cell compartment at a given time point, while leaving the remaining labeled molecules untouched.

A new class of N-phenyl-divinylsulfonamides which can be easily prepared have been successfully developed and utilized as efficient linkers in the field of disulfide bond modification. Functional divinylsulfonamides provide opportunities for the specific introduction of various functionalities, including affinity probes, fluorescent tags, and drugs, into peptides.

Stimuli responsive molecular containers are of great importance for controlled drug delivery and other biomedical applications. Here, we report a new type of acid labile acyclic cucurbit[n]uril (CB[n]) molecular containers, which can degrade and release the encapsulated cargo with accelerated rates under mildly acidic conditions (pH 5.5-6.5). These containers retain the excellent recognition property of CB[n] type hosts. Cell culture study demonstrated that the cellular uptake of cargos could be fine-tuned by complexation with different containers. The release and cell uptake of cargo dye was promoted by acidic pH.

The free fatty acid receptor 1 (FFA1) is a novel antidiabetic target for the treatment of type 2 diabetes based on particular mechanism in amplifying glucose-stimulated insulin secretion. We have previously identified a series of phenoxyacetic acid derivatives. Herein, we describe the further chemical modification of this series directed by ligand efficiency and ligand lipophilicity efficiency. All of these efforts lead to the discovery of the promising candidate 16, an excellent FFA1 agonist with robust agonistic activity (43.6 nM), desired LE and LLE values. Moreover, compound 16 revealed a great potential for improving the hyperglycemia levels in both normal and type 2 diabetic mice without the risk of hypoglycemia even at the high dose of 40 mg/kg.

To investigate the role of Hsp70-2 gene in germ cell apoptosis induced by heat stress, its expression changes were examined in rat normal and unilateral cryptorchid testes by using in situ hybridization, immunohistochemistry, and northern blot analysis techniques. The results showed that the expression level of Hsp70-2 gene declined slightly at the early stage of germ cell apoptosis, and dropped dramatically when most of the germ cells were undergoing apoptosis on day 7.5 after the induction of cryptorchidism. This report suggests for the first time that Hsp70-2 gene might not inhibit the apoptosis of germ cells at the early stage in cryptorchid testes. Hsp70-2 gene does not belong to the immediate early related genes that are responsible for germ cell apoptosis induced by heat stress.