Circular RNAs (circRNAs) represent a distinct group of RNA molecules produced through back-splicing of precursor mRNAs. Their covalently closed structure, which lacks both a 5′ cap and a poly(A) tail, renders them highly resistant to exonucleolytic degradation and contributes to their remarkable intracellular stability. Although circRNAs were historically viewed as noncoding transcripts, accumulating evidence indicates that certain circRNAs can undergo translation under appropriate molecular contexts. Two major modes of noncanonical translation have been described so far: initiation mediated by internal ribosome entry sites (IRESs) and translation triggered by N6-methyladenosine (m6A) modification. Recent studies have revealed that, beyond their canonical classification as non-coding RNAs, circRNAs can give rise to functional peptides through cap-independent translational mechanisms. Accumulating evidence indicates that circRNA-encoded peptides participate in key biological processes during tumor initiation and progression by modulating tumor-associated signaling pathways and protein-protein interaction networks. Functionally, these peptides may promote tumor cell proliferation, migration, invasion, and epithelial-mesenchymal transition, while others exert tumor-suppressive effects by inhibiting oncogenic signaling pathways or interfering with critical protein interactions. Their dual and context-dependent functions highlight the complexity of circRNA-mediated regulation and suggest that these translation products participate in multiple layers of tumor initiation and progression. In this review, we synthesize current knowledge regarding the molecular mechanisms that enable circRNAs to be translated, with particular attention to IRES-driven initiation, m6A-dependent regulation, ribosome accessibility, and the structural determinants required for translation competence. We further summarize well-characterized circRNA-encoded peptides and discuss how they influence tumor-associated signaling networks. In addition, we examine the potential translational applications of these peptides, including their value as diagnostic indicators, prognostic markers, or therapeutic entry points. Their inherent sequence stability, relative expression specificity, and detectability in clinical specimens make circRNA-derived peptides promising candidates for future biomarker and therapeutic development. Overall, circRNA translation research is reshaping our understanding of RNA function and offers new perspectives for studying tumor biology. We propose that expanding investigations into circRNA-encoded peptides will not only improve the mechanistic resolution of cancer research but may also pave the way for innovative strategies in precision oncology, including RNA-based therapeutics and peptide-targeting interventions.

Circular RNAs (circRNAs) represent a distinct group of RNA molecules produced through back-splicing of precursor mRNAs. Their covalently closed structure, which lacks both a 5′ cap and a poly(A) tail, renders them highly resistant to exonucleolytic degradation and contributes to their remarkable intracellular stability. Although circRNAs were historically viewed as noncoding transcripts, accumulating evidence indicates that certain circRNAs can undergo translation under appropriate molecular contexts. Two major modes of noncanonical translation have been described so far: initiation mediated by internal ribosome entry sites (IRESs) and translation triggered by N6-methyladenosine (m6A) modification. Recent studies have revealed that, beyond their canonical classification as non-coding RNAs, circRNAs can give rise to functional peptides through cap-independent translational mechanisms. Accumulating evidence indicates that circRNA-encoded peptides participate in key biological processes during tumor initiation and progression by modulating tumor-associated signaling pathways and protein-protein interaction networks. Functionally, these peptides may promote tumor cell proliferation, migration, invasion, and epithelial-mesenchymal transition, while others exert tumor-suppressive effects by inhibiting oncogenic signaling pathways or interfering with critical protein interactions. Their dual and context-dependent functions highlight the complexity of circRNA-mediated regulation and suggest that these translation products participate in multiple layers of tumor initiation and progression. In this review, we synthesize current knowledge regarding the molecular mechanisms that enable circRNAs to be translated, with particular attention to IRES-driven initiation, m6A-dependent regulation, ribosome accessibility, and the structural determinants required for translation competence. We further summarize well-characterized circRNA-encoded peptides and discuss how they influence tumor-associated signaling networks. In addition, we examine the potential translational applications of these peptides, including their value as diagnostic indicators, prognostic markers, or therapeutic entry points. Their inherent sequence stability, relative expression specificity, and detectability in clinical specimens make circRNA-derived peptides promising candidates for future biomarker and therapeutic development. Overall, circRNA translation research is reshaping our understanding of RNA function and offers new perspectives for studying tumor biology. We propose that expanding investigations into circRNA-encoded peptides will not only improve the mechanistic resolution of cancer research but may also pave the way for innovative strategies in precision oncology, including RNA-based therapeutics and peptide-targeting interventions.

ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m⁶A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m⁶A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m⁶A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.

ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m⁶A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m⁶A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m⁶A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.

OBJECTIVE: To explore early curative effect of upper joint capsule reconstruction combined with biceps tendon transposition in treating irreparable rotator cuff tears. METHODS: From October 2019 to March 2021, 16 patients with irreparable rotator cuff tear were underwent arthroscopic autogenous semitendinosus tendon transplantation for upper articular capsule reconstruction combined with biceps tendon transposition, included 12 males and 4 females, aged from 53 to 72 years old with an average of (62.13±5.35) years old; 3 patients on the left side and 13 patients on the right side. All patients had preoperatively limited joint mobility, resting pain, and mobility pain, and had a history of failure to respond to conservative treatment for more than 8 months. The duration of preoperative symptoms ranged from 45 to 144 months with an average of (85.25±32.08) months. Visual analogue scale (VAS) of shoulder pain, University of California Los Angeles (UCLA) score, Constant-Murley score, active and passive motion of shoulder joint were compared before operation and 2 years after operation, complications were recorded. RESULTS: All 16 patients were followed up for 21 to 32 months with an average of (24.25±3.57) months. There were no complications such as incision infection, vascular and nerve injury, retear occurred. VAS, UCLA and Constant-Murley scores were improved from (5.75±1.18), (11.88±3.38) and (33.38±9.34) before operation to (1.13±0.89), (32.56±2.71), (89.06±6.25) at 2 years after operation (P<0.05). Anterior flexion, abduction, lateral external rotation and lateral internal rotation of shoulder joint were improved from (79.75±21.36) °, (62.06±10.49) °, (19.19±5.41) °, (3.04±0.21) °, respectively to (156.94±13.18) °, (116.19±12.59) °, (42.63±6.07) °, (8.16±0.64) ° at 2 years after operation. Anterior flexion, abduction, lateral lateral rotation and lateral internal rotation of shoulder joint were improved from (116.28±21.47) °, (107.12±9.67) °, (27.62±4.70) °, (4.21±0.41) °, respectively to (165.28±7.15) °, (153.34±4.69) °, (52.46±4.46) °, (9.68±0.68) ° at 2 years after operation, and the difference was statistically significant (P<0.05). CONCLUSION Arthroscopic autograft of semitendinosus tendon combined with transposition of biceps tendon could achieve satisfactory early clinical results in treating patients with irreparable rotator cuff tear, which is a reliable and effective surgical method.
Humans ; Male ; Female ; Middle Aged ; Aged ; Arthroscopy/methods* ; Rotator Cuff Injuries/physiopathology* ; Plastic Surgery Procedures/methods* ; Range of Motion, Articular ; Shoulder Joint/surgery* ; Tendon Transfer

OBJECTIVE: To explore clinical effect of autologous osteochondral transplantation (AOT) in the treatment of recurrent anterior dislocation of the shoulder joint with glenoid cartilage defect in rabbits by establishing a model of recurrent anterior dislocation of the shoulder joint with < 20% glenoid cartilage defect in rabbits. METHODS: Twenty-four male New Zealand white rabbits, aged 6-month-old, weighed (2.69±0.17) kg were selected. The labrum of shoulder joint of rabbits was artificially destroyed to establish a model of recurrent anterior dislocation of shoulder joint with cartilage defect. They were divided into AOT surgery group and simple suture group, with 12 rabbits in each group. AOT group were underwent AOT surgery, while simple suture group was treated with simple Bankart suture for recurrent shoulder joint dislocation. At 6 and 12 weeks after operation, 6 rabbits between two groups were sacrificed for sampling. The dietary conditions, activity conditions, mental states of rabbits and healing conditions of grafts in the specimens were observed and compared between two groups. HE staining was used to observe cell creep, cell morphology, inflammatory cell infiltration, fibrochondrocytes and their arrangement. Masson staining was used to observe the formation and arrangement of collagen fibers; Safrane-green staining was used to observe the regeneration of articular cartilage, subchondral bone and bone tissue. Bone mineral density (BMD), bone volume (BV) and trabecular thickness (Tb.Th) between two groups were measured by Micro-CT to evaluate the remodeling of shoulder glenoid bone defects by autologous osteochondral cartilage. RESULTS: After different surgical interventions were carried out in both groups of rabbits, at 6 weeks after the operation, the abduction, extension, internal rotation and external rotation of the shoulder joint on the operated side showed limited range of motion compared with the contralateral side, while adduction and forward flexion showed no obvious abnormalities compared with the contralateral side. At 12 weeks after operation, the range motion of tshoulder joints in both groups of rabbits had returned to the state before modeling. The effects of HE staining, Masson staining and safrane-green staining at 12 weeks after operation in both groups were stronger than the staining results at 6 weeks after operation. Moreover, the results of HE staining, Masson staining and safranin fixation green staining in AOT group at 6 and 12 weeks after operation were all higher than those in simple suture group. Micro-CT scan results at 6 and 12 weeks after operation showed that BMD (0.427±0.014), (0.466±0.032) g·cm-3, BV(116.171±3.527), (159.327±3.500) mm3, and Tb.Th (0.230±0.006), (0.285±0.009) mm in AOT group, which were higher than those of simple suture group in BMD(0.358±0.011), (0.384±0.096) g·cm-3, BV(72.657±3.903), (118.713±3.860) mm3, and Tb.Th(0.204±0.009), (0.243±0.007) mm;and the differences were statistically significant (P<0.05). CONCLUSION AOT procedure could effectively promote osteogenesis and fibrocartilage regeneration in the cartilage defect area of the shoulder glenoid <20%, which is conducive to reshaping the structure of the shoulder glenoid.
Animals ; Rabbits ; Male ; Transplantation, Autologous ; Cartilage, Articular/injuries* ; Shoulder Dislocation/physiopathology* ; Bone Transplantation ; Shoulder Joint/surgery*

OBJECTIVE: To evaluate the effects of posterior cruciate ligament(PCL) resection on soft tissue elasticity and knee stability in total knee arthroplasty(TKA). METHODS: Six adult cadaveric knee specimens (involving 10 knees) were included in the study. With the assistance of the robotic system(TiRobot Recon, TINAVI, Beijing), total knee arthroplasty (TKA) was performed sequentially using cruciate retaining (CR) prostheses and posterior stabilizing (PS) prostheses. Between the two surgical procedures, the femoral and tibial osteotomy surfaces were not altered;only the posterior cruciate ligament (PCL) was resected and the intercondylar fossa was treated. After installing the femoral trial component, a soft tissue balance solver was used to apply tension ranging from 30 N to 90 N in 5 N increments at 0°, 10°, and 90° of knee flexion. Meanwhile, the medial and lateral joint gaps were measured synchronously. Based on the tension-gap coupling data, the equivalent elastic coefficients of the medial and lateral soft tissue sleeves at different knee flexion angles, as well as the range of the joint line convergence angle (JLCA) under fixed varus-valgus stress, were calculated. Additionally, the gap balance status under 80 N of tension was analyzed. Self-control comparisons of each indicator were conducted before and after PCL resection to analyze the change patterns. RESULTS: After PCL resection, in the fully extended position (knee flexion 0°). The medial equivalent elastic coefficient was 32.2 (25.7, 63.3) N·mm^-1 for the CR prosthesis and 27.7 (22.0, 51.9) N·mm^-1 for the PS prosthesis, and the statistically significant difference (P=0.013). The range of JLCA was 0.41°(0.26, 0.55)° for the CR prosthesis, which was smaller than 0.75° (0.40, 0.98)° for the PS prosthesis, and the difference was statistically significant(P=0.041). At 90° of knee flexion, the medial joint gap was 10.7(10.1, 11.7) mm for the CR prosthesis, which was smaller than 12.1(10.9, 15.1) mm for the PS prosthesis, with a statistically significant difference(P=0.011). No statistically significant differences were observed in other joint gaps. CONCLUSION PCL resection reduces the rigidity of the medial soft tissues in the fully extended knee and increases the medial joint gap in the flexed position, thereby affecting knee stability and balance. This finding suggests that PS and CR prostheses may require different morphological designs, and there should be differences in indications and osteotomy strategies between CR-TKA and PS-TKA. CR-TKA is more suitable for patients with preoperative medial soft tissue laxity.
Humans ; Posterior Cruciate Ligament/physiopathology* ; Knee Joint/physiopathology* ; Arthroplasty, Replacement, Knee ; Elasticity ; Male ; Female ; Middle Aged ; Aged ; Biomechanical Phenomena ; Adult

Recent studies have shown that an imbalance in iron metabolism can affect the composition and microstructural changes of bone, disrupting bone homeostasis and leading to osteoporosis(OP). The imbalance in iron metabolism, along with its induced local abnormal microenvironment and cellular iron death, has become a new focal point in OP research, drawing increasing attention from the academic community regarding the regulation of iron metabolism to prevent and manage OP. From the perspective of traditional Chinese medicine(TCM), iron metabolism imbalance has potential connections to TCM theories regarding internal organs, as well as treatments aimed at tonifying the kidney, strengthening the spleen, and activating blood circulation. Evidence is continually emerging that TCMs and effective components that tonify the kidney, strengthen the spleen, and activate blood circulation can prevent and manage OP by regulating iron metabolism. This article analyzes the relationship between iron and bone, as well as the effects of TCM formulations on improving iron metabolism and influencing bone metabolism, from the perspectives of iron metabolism mechanisms and TCM interventions, aiming to broaden existing clinical strategies for prevention and treatment and inject new momentum into the field of OP as it moves into a new era.
Osteoporosis/drug therapy* ; Humans ; Iron/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Animals ; Medicine, Chinese Traditional ; Bone and Bones/drug effects*

In this study, the reductive amination method was used to label IR783 on Astragalus polysaccharides(APS) for the first time, which was verified by ultraviolet-visible spectroscopy and infrared spectroscopy. Quantitative analysis methods of APS-IR783 in plasma and various tissue were established using a multifunctional microplate reader. The pharmacokinetics and tissue distribution of APS-IR783 in mice were investigated after a single intravenous injection of 30 mg·kg~(-1) APS-IR783, and pharmacokinetic parameters were calculated using DAS 2.0 software. The results showed that the APS used had a mass fraction of 93.69%, a relative molecular weight of 1.55×10~5, and a polydispersity index(PDI, M_w/M_n) of 1.73, close to a homogeneous polysaccharide. The IR783 labeling yield reached 86.50%, and the content of IR783 in APS-IR783 was 0.72%. After a single intravenous injection of 30 mg·kg~(-1), the pharmacokinetic parameters of APS in mouse plasma were as follows: T_(max) was(0.67±0.26) h; C_(max) was(1 599.29±159.30) mg·L~(-1); T_(1/2α) and T_(1/2β) were(2.29±3.06) h and(0.44±0.05) h, respectively; AUC_(0-t) was(23 398.91±2 907.03) mg·h·L~(-1); AUC_(0-∞) was(27 710.55±3 506.55) mg·h·L~(-1); MRT_(0-∞) was(34.38±12.59) h; CL was 0.001 L·h~(-1)·kg~(-1); V_z was(0.042±0.017) L·kg~(-1). The in vivo biodistribution study demonstrated that the in vivo exposure ratios of APS in different tissue were in the following order: spleen > liver > kidney > lung > heart > small intestine > muscle > large intestine > brain > stomach, where the top five tissue accounted for 87.54% of the total area under the curve(AUC). This study successfully labeled APS with a water-soluble near-infrared fluorescent probe of IR783 for the first time and revealed the pharmacokinetics and tissue distribution of APS in mice. The paper provides detailed in vivo behavior of APS after intravenous injection, which lays the foundation for the development and utilization of APS and related natural medicines.
Animals ; Mice ; Polysaccharides/chemistry* ; Tissue Distribution ; Astragalus Plant/chemistry* ; Male ; Drugs, Chinese Herbal/chemistry* ; Fluorescent Dyes/pharmacokinetics* ; Female

Apurinic/apyrimidinic endonuclease 1(APE 1)is a multifunctional protein that plays important roles in DNA repair and regulation of gene expression.Because APE 1 is overexpressed in various cancers,it can serve as a cancer biomarker for aiding clinical diagnosis,guiding therapy,and monitoring prognosis.On this basis,a label-free fluorescent probe was designed based on the primer exchange reaction(PER)strategy for highly sensitive detection of APE 1 activity.In the absence of APE 1,the structure of catalytic hairpin(HP)was stable and could not form G-quadruplex.Therefore,the background fluorescence of this sensing system was very low due to the dissociation of thioflavin T(ThT).In the presence of APE 1,the apurinic/apyrimidinic(AP)site of HP was cleaved by APE 1 and a short nucleic acid fragment that acted as a primer to initiate PER was generated.After PER reaction,a large number of G-quadruplex were produced,which could specifically bind with ThT and resulted in significant increase of fluorescence signal.The combination of low background design of HP and PER amplification made this biosensor had high sensitivity with a detection limit(3σ)of 0.0008 U/mL.Furthermore,the primer sequence was directly generated by the cleavage of APE 1 without additional addition,which not only increased the specificity of the reaction,but also simplified the experiment procedure.Moreover,the use of label-free fluorescence signal reduced the cost of the experiment,and realized rapid detection of APE 1.Finally,this sensor was used to detect APE 1 in human serum samples with spiked recoveries of 91%-104%,proving great potential in study of biological enzyme.