CircHIPK3 prevents chondrocyte apoptosis and cartilage degradation by sponging miR‐30a‐3p and promoting PON2

Osteoarthritis (OA) is a common joint disease featured by the deterioration of articular cartilage and chondrocyte death. Emerging evidence has indicated that circular RNAs (circRNAs) play an essential role in OA progress. Here, we found that the expression of circHIPK3 was significantly decreased in human and mouse OA cartilage. Knocking down circHIPK3 increased apoptosis and intracellular ROS level in HC‐a chondrocytes. We performed proteomic studies and identified that circHIPK3 regulated chondrocyte apoptosis through the mitochondrial pathway. Results of JC‐1 staining and western blot further confirmed that mitochondrial outer membrane permeabilization was promoted in HC‐a chondrocytes transfected by circHIPK3 siRNA. In terms of mechanism, we showed that PON2 functioned as a potential target of circHIPK3 to regulate chondrocyte apoptosis. Moreover, we revealed that circHIPK3 interacted with miR‐30a‐3p to regulate PON2 expression in chondrocytes. Taken together, our findings suggested that circHIPK3 regulated chondrocyte apoptosis by mitochondrial pathway, and targeting the circHIPK3/miR‐30a‐3p/PON2 axis might be a potential strategy for OA treatment.

The current study revealed the important role of circHIPK3 in regulating chondrocyte apoptosis and maintaining extracellular matrix (ECM) homeostasis. Mechanistically, circHIIPK3 might serve as a sponge of miR‐30a‐3p to regulate PON2 expression. The downregulation of circHIIPK3 resulted in the increased expression of miR‐30a‐3p and decreased expression of PON2, thus leading to mitochondrial pathway apoptosis and ECM destruction.     

Tetrahedral framework nucleic acids promote diabetic wound healing via the Wnt signalling pathway

ObjectivesTo determine the therapeutic effect of tetrahedral framework nucleic acids (tFNAs) on diabetic wound healing and the underlying mechanism.Materials and MethodsThe tFNAs were characterized by polyacrylamide gel electrophoresis (PAGE), atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential assays. Cell Counting Kit‐8 (CCK‐8) and migration assays were performed to evaluate the effects of tFNAs on cellular proliferation and migration. Quantitative polymerase chain reaction (Q‐PCR) and enzyme‐linked immunosorbent assay (ELISA) were used to detect the effect of tFNAs on growth factors. The function and role of tFNAs in diabetic wound healing were investigated using diabetic wound models, histological analyses and western blotting.ResultsCellular proliferation and migration were enhanced after treatment with tFNAs in a high‐glucose environment. The expression of growth factors was also facilitated by tFNAs in vitro. During in vivo experiments, tFNAs accelerated the healing process in diabetic wounds and promoted the regeneration of the epidermis, capillaries and collagen. Moreover, tFNAs increased the secretion of growth factors and activated the Wnt pathway in diabetic wounds.ConclusionsThis study indicates that tFNAs can accelerate diabetic wound healing and have potential for the treatment of diabetic wounds.

Tetrahedral framework nucleic acids (tFNAs) can facilitate the proliferation and migration of HaCaTs, HDFs and HUVECs in a high‐glucose environment. tFNAs can accelerate diabetic wound healing by promoting epithelialization, vascularization, collagen synthesis and the secretion of growth factors via the Wnt pathway.     

Effects of highly selective sensory/motor nerve injury on bone metabolism and bone remodeling in rats

Objectives:This work aimed to investigate the mechanism of selective sensory/motor nerve injury in affecting bone metabolism and remodeling.Methods:The selective sensory/motor nerve injury rat model was constructed through posterior rhizotomy (PRG), anterior rhizotomy (ARG), or anterior combined with posterior rhizotomy (APRG) at the L_4-6 sensory/motor nerves on the right side of rats. Sham-operated (SOG) rats served as control. At 8 weeks after surgery, the sciatic nerves, spinal cord segments L₅ and tibial tissues were collected for analysis.Results:the integrity of trabecular bone was damaged, the number of trabecular bone was decreased and the number of osteoclasts were increased in ARG group. ARG activated NF-κβ and PPAR-γ pathways, and inhibited Wnt/β-catenin pathway. ARG group exhibited high turnover bone metabolism. In PRG group, the trabecular bone morphology became thinner, and the number of osteoclasts was increased. NF-κβ pathway was activated and OPG/RANKL ratio was decreased in PRG group. The activated osteoclasts, reduced osteoblasts activity and lower turnover bone metabolism were observed in PRG group. Additionally, the bone metabolism in APRG group was similar to ARG group.Conclusion:The posterior rhizotomy and anterior rhizotomy induced the different degree of osteoporosis in rats, which may attribute to regulate Wnt/β-catenin, NF-κβ and PPAR-γ signalling pathways.     

Suppression of lysosomal-associated protein transmembrane 5 ameliorates cardiac function and inflammatory response by inhibiting the nuclear factor-kappa B (NF-κB) pathway after myocardial infarction in mice

Myocardial infarction (MI) as the remarkable presentation of coronary artery disease is still a reason for morbidity and mortality in worldwide. Lysosomal-associated protein transmembrane 5 (LAPTM5) is a lysosomal-related protein found in hematopoietic tissues and has been confirmed as a positive regulator of pro-inflammatory pathways in macrophages. However, the role of LAPTM5 in MI remains unknown. In this study, we found that both mRNA and protein expression levels of LAPTM5 were significantly elevated in MI mice. Suppression of LAPTM5 in myocardial tissues decreased cardiac fibrosis and improved cardiac function after MI. At the molecular level, downregulated LAPTM5 dramatically suppressed the macrophage activation and inflammatory response via inhibiting the activation of the nuclear factor-kappa B (NF-κB) pathway. Collectively, suppression of LAPTM5 in myocardial tissues inhibits the pro-inflammatory response and the cardiac dysfunction caused by MI. This study indicated that LAPTM5 as a pro-inflammatory factor plays a crucial role in MI disease.     

Endocytosis of Peptidase Inhibitor SerpinE2 promotes Myocardial Fibrosis through activating ERK1/2 and β-catenin Signaling Pathways

Cardiac fibrosis is one of the common pathological processes in many cardiovascular diseases characterized by excessive extracellular matrix deposition. SerpinE2 is a kind of protein that inhibits peptidase in extracellular matrix and up-regulated tremendously in mouse model of cardiac fibrosis induced by pressure-overloaded via transverse aortic constriction (TAC) surgery. However, its effect on cardiac fibroblasts (CFs), collagen secretion and the underlying mechanism remains unclear. In this study, DyLight® 488 green fluorescent dye or His-tagged proteins were used to label the exogenous serpinE2 protein. It was showed that extracellular serpinE2 translocated into CFs by low-density lipoprotein receptor-related protein 1 (LRP1) and urokinase plasminogen activator receptor (uPAR) of cell membrane through endocytosis. Knockdown of LRP1 or uPAR reduced the level of serpinE2 in CFs and down-regulated the collagen expression. Inhibition of the endocytosis of serpinE2 could inhibit ERK1/2 and β-catenin signaling pathways and subsequently attenuated collagen secretion. Knockdown of serpinE2 attenuates cardiac fibrosis in TAC mouse. We conclude that serpinE2 could be translocated into cardiac fibroblasts due to endocytosis through directly interact with the membrane protein LRP1 and uPAR, and this process activated the ERK1/2, β-catenin signaling pathways, consequently promoting collagen production.     

Influence of nitrogen sources on the tolerance of Lacticaseibacillus rhamnosus to heat stress and oxidative stress

It has been found that 32 genes related to nitrogen source metabolism in Lacticaseibacillus rhamnosus are downregulated under both heat stress and oxidative stress. In this study, the influence of different nitrogen sources within the growth medium on the tolerance of L. rhamnosus to heat stress and oxidative stress was investigated. Tryptone-free MRS was found to enhance the tolerance of L. rhamnosus hsryfm 1301 to heat stress and oxidative stress during the whole growth period, and this result was universal for all L. rhamnosus species analyzed. The strongest strengthening effect occurred when the OD₆₀₀ value reached 2.0, at which the survival rates under heat stress and oxidative stress increased 130-fold and 40-fold, respectively. After supplementing phenylalanine, isoleucine, glutamate, valine, histidine, or tryptophan into the tryptone-free MRS, the tolerance of L. rhamnosus to heat stress and oxidative stress exhibited a sharp drop. The spray drying survival rate of L. rhamnosus hsryfm 1301 cultured in the tryptone-free MRS rose to 75% (from 30%), and the spray dried powder also performed better in the experimentally simulated gastrointestinal digestion. These results showed that decreasing the intake of amino acids is an important mechanism for L. rhamnosus to tolerate heat stress and oxidative stress. When L. rhamnosus is cultured for spray drying, the concentration of the nitrogen source''s components should be an important consideration.