Cyclic stretch induced epigenetic activation of periodontal ligament cells.

Periodontal ligament (PDL) cells play a crucial role in maintaining periodontal integrity and function by providing cell sources for ligament regeneration. While biophysical stimulation is known to regulate cell behaviors and functions, its impact on epigenetics of PDL cells has not yet been elucidated. Here, we aimed to investigate the cytoskeletal changes, epigenetic modifications, and lineage commitment of PDL cells following the application of stretch stimuli to PDL. PDL cells were subjected to stretching (0.1 Hz, 10 %). Subsequently, changes in focal adhesion, tubulin, and histone modification were observed. The survival ability in inflammatory conditions was also evaluated. Furthermore, using a rat hypo-occlusion model, we verified whether these phenomena are observed in vivo. Stretched PDL cells showed maximal histone 3 acetylation (H3Ace) at 2 h, aligning perpendicularly to the stretch direction. RNA sequencing revealed stretching altered gene sets related to mechanotransduction, histone modification, reactive oxygen species (ROS) metabolism, and differentiation. We further found that anchorage, cell elongation, and actin/microtubule acetylation were highly upregulated with mechanosensitive chromatin remodelers such as H3Ace and histone H3 trimethyl lysine 9 (H3K9me3) adopting euchromatin status. Inhibitor studies showed mechanotransduction-mediated chromatin modification alters PDL cells behaviors. Stretched PDL cells displayed enhanced survival against bacterial toxin (C12-HSL) or ROS (H2O2) attack. Furthermore, cyclic stretch priming enhanced the osteoclast and osteoblast differentiation potential of PDL cells, as evidenced by upregulation of lineage-specific genes. In vivo, PDL cells from normally loaded teeth displayed an elongated morphology and higher levels of H3Ace compared to PDL cells with hypo-occlusion, where mechanical stimulus is removed. Overall, these data strongly link external physical forces to subsequent mechanotransduction and epigenetic changes, impacting gene expression and multiple cellular behaviors, providing important implications in cell biology and tissue regeneration.

Hierarchically porous surface of HA-sandblasted Ti implant screw using the plasma electrolytic oxidation: Physical characterization and biological responses.

The surface topological features of bioimplants are among the key indicators for bone tissue replacement because they directly affect cell morphology, adhesion, proliferation, and differentiation. In this study, we investigated the physical, electrochemical, and biological responses of sandblasted titanium (SB-Ti) surfaces with pore geometries fabricated using a plasma electrolytic oxidation (PEO) process. The PEO treatment was conducted at an applied voltage of 280 V in a solution bath consisting of 0.15 mol L-1 calcium acetate monohydrate and 0.02 mol L-1 calcium glycerophosphate for 3 min. The surface chemistry, wettability, mechanical properties and corrosion behavior of PEO-treated sandblasted Ti implants using hydroxyapatite particles (PEO-SB-Ti) were improved with the distribution of calcium phosphorous porous oxide layers, and showed a homogeneous and hierarchically porous surface with clusters of nanopores in a bath containing calcium acetate monohydrate and calcium glycerophosphate. To demonstrate the efficacy of PEO-SB-Ti, we investigated whether the implant affects biological responses. The proposed PEO-SB-Ti were evaluated with the aim of obtaining a multifunctional bone replacement model that could efficiently induce osteogenic differentiation as well as antibacterial activities. These physical and biological responses suggest that the PEO-SB-Ti may have a great potential for use an artificial bone replacement compared to that of the controls.

Strontium/Silicon/Calcium-Releasing Hierarchically Structured 3D-Printed Scaffolds Accelerate Osteochondral Defect Repair.

Articular cartilage defects are a global challenge, causing substantial disability. Repairing large defects is problematic, often exceeding cartilage's self-healing capacity and damaging bone structures. To tackle this problem, we develop a scaffold-mediated therapeutic ion delivery system. These scaffolds are constructed from poly(ε-caprolactone) and strontium (Sr)-doped bioactive nanoglasses (SrBGn), creating a unique hierarchical structure featuring macro-pores from 3D printing, micro-pores, and nano-topologies due to SrBGn integration. The SrBGn-embedded scaffolds (SrBGn-µCh) release Sr, silicon (Si), and calcium (Ca) ions, which improve chondrocyte activation, adhesion, proliferation, and maturation-related gene expression. This multiple ion delivery significantly affects metabolic activity and maturation of chondrocytes. Importantly, Sr ions may play a role in chondrocyte regulation through the Notch signaling pathway. Notably, the scaffold's structure and topological cues expedite the recruitment, adhesion, spreading, and proliferation of chondrocytes and bone marrow-derived mesenchymal stem cells. Si and Ca ions accelerate osteogenic differentiation and blood vessel formation, while Sr ions enhance the polarization of M2 macrophages. Our findings show that SrBGn-µCh scaffolds accelerate osteochondral defect repair by delivering multiple ions and providing structural/topological cues, ultimately supporting host cell functions and defect healing. This scaffold holds great promise for osteochondral repair applications. This article is protected by copyright. All rights reserved.

Development of an Injectable Biphasic Hyaluronic Acid-Based Hydrogel With Stress Relaxation Properties for Cartilage Regeneration.

Biomimetic stress-relaxing hydrogels with reversible crosslinks attract significant attention for stem cell tissue regeneration compared with elastic hydrogels. However, stress-relaxing hyaluronic acid (HA)-based hydrogels fabricated using conventional technologies lack stability, biocompatibility, and mechanical tunability. Here, it is aimed to address these challenges by incorporating calcium or phosphate components into the HA backbone, which allows reversible crosslinking of HA with alginate to form interpenetrating networks, offering stability and mechanical tunability for mimicking cartilage. Diverse stress-relaxing hydrogels (τ1/2; SR50, 60-2000 s) are successfully prepared at ≈3 kPa stiffness with self-healing and shear-thinning abilities, favoring hydrogel injection. In vitro cell experiments with RNA sequencing analysis demonstrate that hydrogels tune chondrogenesis in a biphasic manner (hyaline or calcified) depending on the stress-relaxation properties and phosphate components. In vivo studies confirm the potential for biphasic chondrogenesis. These results indicate that the proposed stress-relaxing HA-based hydrogel with biphasic chondrogenesis (hyaline or calcified) is a promising material for cartilage regeneration.

Targeting Nuclear Mechanics Mitigates the Fibroblast Invasiveness in Pathological Dermal Scars Induced by Matrix Stiffening.

Pathological dermal scars such as keloids present significant clinical challenges lacking effective treatment options. Given the distinctive feature of highly stiffened scar tissues, deciphering how matrix mechanics regulate pathological progression can inform new therapeutic strategies. Here, it is shown that pathological dermal scar keloid fibroblasts display unique metamorphoses to stiffened matrix. Compared to normal fibroblasts, keloid fibroblasts show high sensitivity to stiffness rather than biochemical stimulation, activating cytoskeletal-to-nuclear mechanosensing molecules. Notably, keloid fibroblasts on stiff matrices exhibit nuclear softening, concomitant with reduced lamin A/C expression, and disrupted anchoring of lamina-associated chromatin. This nuclear softening, combined with weak adhesion and high contractility, facilitates the invasive migration of keloid fibroblasts through confining matrices. Inhibiting lamin A/C-driven nuclear softening, via lamin A/C overexpression or actin disruption, mitigates such invasiveness of keloid fibroblasts. These findings highlight the significance of the nuclear mechanics of keloid fibroblasts in scar pathogenesis and propose lamin A/C as a potential therapeutic target for managing pathological scars.

[Impact of Climate Warming on Paddy Soil Organic Carbon Change in the Sichuan Basin of China].

Climate warming can increase soil temperature and lead to soil carbon release, but it can also increase soil organic carbon by increasing primary productivity. Cropland soils are considered to have a huge potential to sequester carbon; however, direct observations for the responses of cropland soil organic carbon to climate warming over broad geographic scales are rarely documented. Paddy soil is one of the important cultivated soils in China. Based on the data of 2217 sampling points obtained during the second national soil survey and the data of 2382 sampling points collected during 2017-2019, this study analyzed the change characteristics of soil organic carbon content of paddy surface soil in Sichuan Basin of China and explored the relationships between the soil organic carbon change of paddy soil and temperature, precipitation, cropland use type, fertilization intensity, and grain yield. The results showed that the content of soil organic carbon of paddy soil changed from 13.33 g·kg-1to 15.96 g·kg-1, with an increase of 2.63 g·kg-1, suggesting that soils in the Sichuan Basin have acted as a carbon sink over past 40 years. The soil organic carbon increment of paddy soil varied with different geomorphic regions and different secondary basins. The increase in SOC content in paddy soil was positively correlated with annual average temperature; negatively correlated with annual average precipitation; and initially increased and then decreased with annual average fertilizer application, annual average increase rate of fertilizer application, annual average grain yield, and annual average grain yield growth rate. The relationship between the increase in SOC content and the annual average temperature growth rate was different under different farmland utilizations, and the increase in the annual average temperature growth rate had significant effects with the increase in SOC content only on paddy-dryland rotation. These results indicate that the paddy soil organic carbon change in Sichuan Basin was co-affected by various factors, but climate warming was an important factor leading to the paddy soil organic carbon change, and its influence was controlled by the water conditions determined by farmland use.

A comparison of behavioral paradigms assessing spatial memory in tree shrews.

Impairments in spatial navigation in humans can be preclinical signs of Alzheimer's disease. Therefore, cognitive tests that monitor deficits in spatial memory play a crucial role in evaluating animal models with early stage Alzheimer's disease. While Chinese tree shrews (Tupaia belangeri) possess many features suitable for Alzheimer's disease modeling, behavioral tests for assessing spatial cognition in this species are lacking. Here, we established reward-based paradigms using the radial-arm maze and cheeseboard maze for tree shrews, and tested spatial memory in a group of 12 adult males in both tasks, along with a control water maze test, before and after bilateral lesions to the hippocampus, the brain region essential for spatial navigation. Tree shrews memorized target positions during training, and task performance improved gradually until reaching a plateau in all 3 mazes. However, spatial learning was compromised post-lesion in the 2 newly developed tasks, whereas memory retrieval was impaired in the water maze task. These results indicate that the cheeseboard task effectively detects impairments in spatial memory and holds potential for monitoring progressive cognitive decline in aged or genetically modified tree shrews that develop Alzheimer's disease-like symptoms. This study may facilitate the utilization of tree shrew models in Alzheimer's disease research.

Egg quality, hatchability, gosling quality, and amino acid profile in albumen and newly-hatched goslings' serum as affected by egg storage.

In modern poultry husbandry, storing fertilized eggs is a common measure to cope with the variable demands of the market and the maximum hatching capacity of the hatchery. However, this measure is harmful to the hatchability of eggs and the quality of newly hatched birds. Knowledge about the effects of storing fertilized eggs on the performance of goslings is still limited. The objective of this study was to investigate the effects of storing fertilized eggs on egg quality, hatchability, gosling quality, hatching weight, post-hatching growth performance, and amino acid profile in albumen and newly hatched goslings' serum. A total of 1,080 fertilized goose eggs (Jilin White goose) with a similar egg weight (126.56 ± 0.66 g) were used in this study. All eggs were distributed into 3 groups with 24 replicates per group and 15 eggs per replicate. The differences between groups were the storage duration of eggs (0, 7, or 14 d). We found that the Haugh unit, yolk weight, and eggshell weight decreased linearly, whereas the albumen pH increased linearly, with storage duration. Prolonging storage duration had negative effects on hatchability, hatching weight, post-hatching growth performance parameters, and gosling quality in a time-dependent manner. The analysis of the amino acid profile in albumen and newly-hatched goslings' serum showed that the amino acid content increased linearly with storage duration. Additionally, eggs stored for 14 d had the worst performance for all measured parameters. Therefore, we concluded that the storage of fertilized eggs negatively affects egg quality and post-hatching gosling quality. To produce high-quality goslings, it is necessary to shorten the storage duration for fertilized eggs.

Development of small intestine and sugar absorptive capacity in goslings during pre- and post-hatching periods.

This study was conducted to investigate the development patterns of small intestine, intestinal morphology, disaccharidase activities, and sugar transporter gene expression in goslings during pre- and post-hatching periods. Small intestine was sampled on embryonic d 23 and 27, day of hatch, and d 1, 4, and 7 post-hatching. A total of 18 eggs with the breed of Jilin White geese were selected at each sampling timepoint for measuring relevant parameters. Three eggs were considered as a group, with 6 groups in each sampling timepoint. Rapid development of small intestine was observed around the hatching, of which jejunum and ileum had relatively higher development rates. Villus surface area from three intestinal segments started to increase on embryonic d 27, and kept relatively stable during day of hatch to d 1 post-hatching, and following increased till d 7 post-hatching. A high priority of villi enrichment was observed in duodenum and jejunum. The activity of disaccharidase increased before hatching and kept relatively high-level post-hatching, of which the activity of disaccharidase was highest in jejunum. The expression of sugar transporter gene increased prior to hatching and then decreased post-hatching, of which jejunum and duodenum were sites with high sugar transporter gene expression. Rapid development in intestinal morphology, disaccharidase activities, and sugar transporter gene expression around the hatching indicated that goslings have high potential to digest and/or assimilate carbohydrates during its early-life, which provided a preparation for further digestion of exogenous feed. This study provided a profile of development patterns for intestinal morphology, disaccharidase activities, and sugar transporter gene expression in goslings, which was beneficial to understanding the characteristics of nutrient absorption during the early-life of goslings.

Ultra-early weaning alters growth performance, hematology parameters, and fecal microbiota in piglets with same genetic background.

Piglets with the same genetic background were used to investigate the effects of different lengths of suckling period on growth performance, hematology parameters, and fecal microbiota. All piglets were born by a sow (Landrace×Yorkshire). On day 14 postpartum, a total of 16 piglets [Duroc×(Landrace×Yorkshire)] with a similar initial body weight (2.48 ± 0.25 kg) were randomly assigned into two groups with four replicates per group, two pigs per replicate pen (one barrow and one gilt). On day 14 of age, experiment started, piglets from the first group were weaned (14W), whereas the others continued to receive milk until day 28 of age (28W). The experiment completed on day 70 of age, last 56 days. Growth performance parameters including body weight, average daily gain, feed intake, feed efficiency, and growth rate and hematology parameters including immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), albumin, globulin, and total protein were measured in this study. Additionally, a technique of 16S rRNA gene sequencing was used to analyze fecal microbiota for revealing how the changes in the lengths of suckling period on intestinal microbiota. We found that ultra-early weaning impaired growth performance of piglets, whose worse body weight, average daily gain, feed intake, feed efficiency, and growth rate were observed in 14W group at all measured timepoints in comparison with those in 28W group (P < 0.05). Moreover, higher contents of serum IgA (P = 0.028), IgG (P = 0.041), and IgM (P = 0.047), as well as lower contents of serum albumin (P = 0.002), albumin-to-globulin ratio (P = 0.003), and total protein (P = 0.004), were observed in 14W group in comparison with those in 28W group on day 28 of age, but not on day 70 of age. High-throughput pyrosequencing of 16S rRNA indicated that the intestinal microbiota richness in 14W group was lower than that in 28W group (P < 0.05); moreover, in comparison with 28W group at all sampling timepoints, fecal microbiota in 14W group showed more beneficial bacteria and fewer pathogenic bacteria (P < 0.05). Therefore, we considered that ultra-early weaning had positive effects on immune status and fecal microbiota composition in piglets, but negative effects on growth performance and fecal microbiota abundance.

Microbial Diversity Analyses of Fertilized Thitarodes Eggs and Soil Provide New Clues About the Occurrence of Chinese Cordyceps.

Chinese cordyceps is a well-known fungus-larva complex with medicinal and economic importance. At present the occurrence of Chinese cordyceps has not been fully illuminated. In this study, the microbial diversities of fertilized Thitarodes eggs from sites A (high occurrence rates of Chinese cordyceps), B (low occurrence rates), and C (no Chinese cordyceps) were analyzed using 16S rRNA and ITS gene-sequencing technique. The previous sequencing data of soil from the same sites were conjointly analyzed. The results showed that bacterial communities among the eggs were significantly different. The bacterial diversity and evenness were much higher on site A. Wolbachia was overwhelmingly predominant in the eggs of sites B and C, while Spiroplasma showed preference on site A. The fungal between-group differences in the eggs were not as significant as that of bacteria. Purpureocillium in Cordyceps-related families showed preference on site A. Wolbachia, Spiroplasma, and Purpureocillium were inferred to be closely related to Chinese cordyceps occurrence. Intra-kingdom and inter-kingdom network analyses suggest that closer correlations of microbial communities (especially closer fungal positive correlations) in fertilized eggs might promote Chinese cordyceps occurrence. Besides, metabolic pathway analysis showed that in fertilized eggs or soil the number of bacterial metabolic pathways with significant differences in every comparison between two sites was greater than that of fungi. Collectively, this study provides novel information about the occurrence of Chinese cordyceps, contributing to the large-scale artificial cultivation of Chinese cordyceps.

Collective enantioselective total synthesis of (+)-sinensilactam A, (+)-lingzhilactone B and (-)-lingzhiol: divergent reactivity of styrene.

The collective total synthesis of (+)-sinensilactam A, (+)-lingzhilactone B, (+)-lingzhilactone C and (-)-lingzhiol has been accomplished from a common epoxide intermediate 9. Chemoselective epoxy opening with either an aryl or alkene moiety of styrene led to different carbon skeletons, which can be advanced to a divergent and concise total synthesis of four meroterpenoids.

Synthesis and Cytotoxicities of Royleanone Derivatives.

Carnosic acid was used as starting material to synthesize royleanone derivatives featured C11-C14 para quinone. The importance of C-20 group of royleanone derivatives was verified by the cytotoxicity assay of royleanonic acid, miltionone I and deoxyneocrptotanshinone. Following our synthetic route, 15 amide derivatives were synthesized and 8 compounds exhibited moderate cytotoxic activities against three human cancer lines in vitro.