Harnessing Nucleic Acids Nanotechnology for Bone/Cartilage Regeneration

The effective regeneration of weight-bearing bone defects and critical-sized cartilage defects remains a significant clinical challenge. Traditional treatments such as autologous and allograft bone grafting have not been successful in achieving the desired outcomes, necessitating the need for innovative therapeutic approaches. Nucleic acids have attracted significant attention due to their ability to be designed to form discrete structures and programmed to perform specific functions at the nanoscale. The advantages of nucleic acid nanotechnology offer numerous opportunities for in-cell and in vivo applications, and hold great promise for advancing the field of biomaterials. In this review, the current abilities of nucleic acid nanotechnology to be applied in bone and cartilage regeneration are summarized and insights into the challenges and future directions for the development of this technology are provided.     

Entrainment of endangered sturgeon by a large water diversion: Rescue,enumeration, and conservation opportunities

The Bonnet Carre' Spillway diverts water from the Mississippi River through a floodway into brackish Lake Pontchartrain to reduce river stages at New Orleans and prevent flood damage. Pallid Sturgeon Scaphirhynchus albus, a federally listed species under the Endangered Species Act, and Shovelnose Sturgeon Scaphirhynchus platorynchus, listed under the Similarity of Appearance rule, are entrained through the spillway structure and become trapped in the canals and shallow lakes. The two species of sturgeon were identified according to a suite of morphomeristic characters, not genetically, and were therefore noted as either Shovelnose Sturgeon or presumed Pallid Sturgeon. Rescue efforts were undertaken to return the entrained sturgeon back into the Mississippi River. This article describes the environmental and operational conditions that influence entrainment risk, catch, and potential impacts on the population. Five openings and corresponding rescue operations occurred between 2008 and 2019 after each spillway closure. A total of 70 days with a crew number ranging from 6 to 12 were expended to collect 57 Pallid Sturgeon, four of which were dead, and 362 Shovelnose Sturgeon, 83 of which were dead, after the five openings that spanned 240 total days. More sturgeon were entrained at higher water temperatures, with a greater number of bays opened for longer durations. Recovery of sturgeon is initially high but over time declines as sturgeon are depleted from the floodway, stranded in isolated waterbodies in the floodway, and/or displaced further downstream into Lake Pontchartrain during longer openings. Sturgeon that cannot find their way back to the floodway are unlikely to be rescued. Recent population studies indicate that only a small proportion of the Lower Mississippi River total population is entrained. However, this does not take into account those individuals entrained but not captured and the potential impacts if more frequent openings of the structure were to continue in the future. Conservation recommendations are provided to increase catch efficiency and recovery of the endangered sturgeon.     

Unfolding the Mystery Behind the Onset of Chondrocyte Hypertrophy during Chondrogenesis: Toward Designing Advanced Permanent Cartilage-mimetic Biomaterials

Successful recapitulation of the anatomical microarchitecture and biomechanics of the native articular cartilage under in vitro culture conditions is still an elusive topic of research. The major roadblock lies in maintaining the stable chondrogenic phenotype in vivo or under long-term in vitro conditions. Tissue engineers worldwide has coined this aberrant loss of permanent cartilage characteristics to transient cartilage form as “chondrocyte hypertrophy”. Although the following has been validated through the expression of a few known markers but very little is understood regarding the molecular mechanism that dwells underneath. This review summarizes the precise aetiology behind the development and progression of the hypertrophic phenotype in chondrocytes under in vitro chondrogenic conditions. Based on the current literature survey, it is deciphered that the type of cell utilized (chondrocytes or stem cells), the chondrogenic culture conditions (growth factors/biochemical mediators) and the culture microenvironment (oxygen tension, mechanical loading) during chondrogenesis have a direct correlation with the dysregulated activity of the chondrogenic signaling pathways corroborating the onset of hypertrophic maturation of chondrocytes. Furthermore, it is critically analyzed whether to completely inhibit these hypertrophy-inducing signaling pathways or apply a brake in terms of time-dependent dose due to their functional duality role in chondrogenesis.     

同时测定软骨酶解物中硫酸软骨素及透明质酸含量的高效液相色谱法的建立

为了准确快速同时测定软骨酶解物中硫酸软骨素和透明质酸含量，以半乳糖胺和葡萄糖胺为测定目标物，通过优化色谱条件和方法性试验，建立了一种高效液相色谱的测定方法。使用ZORBAX C18柱分离，用乙腈和乙酸铵溶液为流动相进行梯度洗脱，流速为1.00 mL/min，在波长250 nm下测定。方法性试验表明，硫酸软骨素和透明质酸的质量浓度在100~500 mg/L范围与峰面积线性关系良好，其中硫酸软骨素的检出限为0.948 mg/L，重复性偏差0.089%，平均回收率99.71%，相对偏差0.35%；透明质酸的检出限为0.027 mg/L，重复性偏差0.045%，平均回收率97.74%，相对偏差0.92%。与传统方法相比，该法具有受杂质干扰影响小，准确度高，重复性优异，回收率以及精确度高的优势，可以实现准确快速同时测定软骨酶解物中硫酸软骨素和透明质酸的含量。     

An Injectable Enzymatically Crosslinked and Mechanically Tunable Silk Fibroin/Chondroitin Sulfate Chondro-Inductive Hydrogel

An injectable hybrid hydrogel is synthesized, comprising silk fibroin (SF) and chondroitin sulfate (CS) through di-tyrosine formation bond of SF chains. CS and SF are reported with excellent biocompatibility as tissue engineering scaffolds. Nonetheless, the rapid degradation rate of pure CS scaffolds presents a challenge to effectively recreate articular cartilage. As CS is one of the cartilage extracellular matrix (ECM) components, it has the potential to enhance the biological activity of SF-based hydrogel in terms of cartilage repair. Therefore, altering the CS concentrations (i.e., 0 wt%, 0.25 wt%, 0.5 wt%, 1 wt%, and 2 wt%), which are interpenetrated between SF β-sheets and chains, can potentially adjust the physical, chemical, and mechanical features of these hybrid hydrogels. The formation of β-sheets by 30 days of immersion in de-ionized (DI) water can improve the compression strength of the SF/CS hybrid hydrogels in comparison with the same SF/CS hybrid hydrogels in the dried state. Biological investigation and observation depicts proper cell attachment, proliferation and cell viability for C28/I2 cells. Gene expression of sex-determining region YBox 9 (SOX9), Collagen II α1, and Aggrecan (AGG) exhibits positive C3H10T1/2 growth and expression of cartilage-specific genes in the 0.25 wt% and 0.5 wt% SF/CS hydrogels.     

Localization of Lesion Cells and Targeted Mitochondria Via Embedded Hydrogel Microsphere using Heat Transfer Microneedles

The localization of lesion cells and targeted regulation of organelle function can promote the lesion repair. However, conventional regulation is difficult to reach deep lesions and target mitochondria. In this study, dynamic spiral Mosaic technology is ued to construct heat transfer microneedles with spiral Mosaic micro/nano hydrogel microspheres (ST-needle), using molecular chain motion in response to heat stimulation to regulate the adhesion of non-oriented triblock polymer, as a dual delivery system for heat energy and biological factors. The ST-needle system use its physical property to accurately reach the deep lesions and transfer heat to the lesion cells. Heat activates the dynamic spiral Mosaic mechanism of the ST-needle system, removing the Mosaic state of hydrogel microspheres and realizing the arrival of heat and hydrogel microspheres into lesion together. Through the rapid inhibition of mitochondrial apoptosis by heat, and long-term induce mitophagy by hydrogel microspheres releasing biological factors, finally complete the synergistic targeted regulation of mitochondrial function. In vitro/vivo experiments show that ST-needle system can inhibit chondrocyte apoptosis more effectively (64.41% lower than conventional regulation). Based on dynamic spiral Mosaic technique and the synergistic regulation of heat and biological factors, the ST-needle system is a promising method for lesion repair.     

Self-Assemble Silk Fibroin Microcapsules for Cartilage Regeneration through Gene Delivery and Immune Regulation

Effective treatments for cartilage defects are currently lacking. Gene delivery using proper delivery systems has shown great potential in cartilage regeneration. However, the inflammatory microenvironment generated by the defected cartilage severely affects the system's delivery efficiency. Therefore, this study reports a silk fibroin microcapsule (SFM) structure based on layer-by-layer self-assembly, in which interleukin-4 (IL-4) is modified on silk by click chemistry and loaded with lysyl oxidase plasmid DNA (LOX pDNA). The silk microcapsules display good biocompatibility and the release rate of genes can be adjusted by controlling the number of self-assembled layers. Moreover, the functionalized SFMs mixed with methacrylated gelatin (GelMA) exhibit good injectability. The IL-4 on the outer layer of the SFM can regulate macrophages to polarize toward the M2 type, thereby promoting cartilage matrix repair and inhibiting inflammation. The LOX pDNA loaded inside can be effectively delivered into cells to promote extracellular matrix generation, significantly promoting cartilage regeneration. The results of this study provide a promising biomaterial for cartilage repair, and this novel silk-based microcapsule delivery system can also provide strategies for the treatment of other diseases.     

Amelioration of Osteoarthritis via Tetrahedral Framework Nucleic Acids Delivering Microrna-124 for Cartilage Regeneration

MicroRNAs (miRNAs) regulate several physiological and pathological processes involved in various diseases, including osteoarthritis (OA). OA is the most common global musculoskeletal disorder, characterized by the irreversible progressive destruction of articular cartilage. Supplementation with exogenous miRNAs may represent a promising therapeutic OA treatment, with miRNA-124 (miR-124) being a prime candidate for its anti-inflammatory ability; however, an effective drug delivery system is urgently required to enhance miR-124 stability and capacity to enter chondrocytes. To this end, tetrahedral framework nucleic acids’ (tFNAs) self-assembled 3D DNA nanostructures possess superior inherent biocompatibility, versatile functionality, unsurpassed editability, and strong cellular internalization ability. In this study, tFNAs carrying one or three miR-124 (T-miR1 or T-miR3) are successfully synthesized. T-miR3 is largely absorbed via induced inflammatory chondrocytes by IL-1β. With reactive oxygen species’ scavenging ability and inflammation-suppressive miR-124 release behavior, T-miR3 efficiently protects chondrocytes against IL-1β injury in vitro. Additionally, T-miR3 effectively prevents OA progression by inhibiting chondrocyte apoptosis, smoothing cartilage surfaces, suppressing extracellular matrix degradation, and increasing synovial thickness, effectively protecting in vivo articular cartilage, and illustrating the therapeutic ability of T-miR3 in OA treatment. This study provides experimental evidence and novel therapeutic strategies for OA treatment in the clinical setting.     

植物乳杆菌AR495通过降低关节组织炎症水平改善大鼠骨关节炎

植物乳杆菌AR495(Lactobacillus plantarum AR495)具有良好的抗炎、缓解骨质疏松作用。为进一步探讨L. plantarum AR495缓解骨关节炎（osteoarthritis,OA）的效果和作用机制，本实验建立了OA大鼠模型，考察L. plantarum AR495对OA大鼠骨关节炎标志物、炎症因子水平以及氧化应激损伤等指标的影响，并通过关节部位病理学染色和Micro-CT检测以验证软骨基质和骨质恢复情况。结果显示，L. plantarum AR495能够显著缓解OA大鼠因活动量减少而导致的体质量过度增长（P<0.05）；病理分析表明，L. plantarum AR495能够显著降低OA大鼠关节组织中炎症因子肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)水平（P<0.05），抑制金属基质蛋白酶-13(matrix metalloproteinase-13,MMP-13)和软骨基质降解物II型胶原C端肽（C-telopeptideoftypeIIcollagen,CTX-II）的生成（P<0.05），从而缓解...     

Glycerol-modified poly(vinyl alcohol)/poly(ethylene glycol) self-healing hydrogel for artificial cartilage

Poly(vinyl alcohol) (PVA) hydrogels have shown potential applications in bionic articular cartilage due to their tissue-like viscoelasticity, good biocompatibility and low friction. However, their lack of adequate mechanical properties is a key obstacle for PVA hydrogels to replace natural cartilage. In this study, poly(ethylene glycol) (PEG) and glycerol were introduced into PVA, and a PVA/PEG–glycerol composite hydrogel was synthesized using a mixing physical crosslinking method. The mechanical properties, hydrophilicity and tribological behavior of the PVA/PEG–glycerol hydrogel were investigated by changing the concentration of glycerol in PEG. The results showed that the tensile strength of the hydrogel reached 26.6 MPa at 270% elongation at break with 20 wt% of glycerol plasticizer, which satisfied the demand of natural cartilage. In addition, the excellent hydrophilicity of glycerol provides good lubricating properties for the composite gel under dry friction. Meanwhile, self-healing and cellular immunity assays demonstrated that the composite gel could have good self-healing ability and excellent biocompatibility even in the absence of external stimuli. This study provides a new candidate material for the design of articular cartilage, which has the potential to facilitate advances in artificial joint cartilage repair. © 2022 Society of Industrial Chemistry.