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Abstract Intervertebral disc degeneration (IVDD) is a leading cause of low back pain, with limited effective treatments due to an incomplete understanding of disease mechanisms. In this study, we report that circFUNDC1, a nuclear circular RNA, is markedly downregulated in nucleus pulposus cells (NPCs) from patients with end-stage IVDD. CircFUNDC1 is derived from the gene encoding the FUN14 domain-containing 1 (FUNDC1) protein, which is essential for mitophagy and cell survival. Functional analyses reveal that circFUNDC1 plays a crucial role in maintaining extracellular matrix homeostasis by enhancing the expression of anabolic factors in NPCs. Additionally, we identified the transcriptional regulator cyclin-dependent kinase 9 (CDK9) as a novel binding partner for circFUNDC1. Binding with circFUNDC1 recruits CDK9 via complementary nucleotides to the FUNDC1 promoter to stimulate the production of full-length FUNDC1 mRNAs and proteins, forming a positive feedback loop. Overexpression of circFUNDC1 protects NPCs from oxidative stress by promoting mitophagy, reducing reactive oxygen species levels, and inhibiting cellular senescence. Moreover, circFUNDC1 overexpression delays the onset of IVDD in an ex-vivo culture model. This study is the first to demonstrate that circFUNDC1 is vital for protecting NPCs from oxidative stress, suggesting circFUNDC1 as a potential therapeutic target for IVDD.

Abstract Background Circular RNAs (circRNAs) have risen to prominence as important regulators of biological processes. This study investigated whether circGNB1 functions as a competitive endogenous RNA to regulate the pathological process of oxidative stress in age‐related osteoarthritis (OA). Methods The relationship between circGNB1 expression and oxidative stress/OA severity was determined in cartilages from OA patients at different ages. The biological roles of circGNB1 in oxidative stress and OA progression, and its downstream targets were determined using gain‐ and loss‐of‐function experiments in various biochemical assays in human chondrocytes (HCs). The in vivo effects of circGNB1 overexpression and knockdown were also determined using a destabilization of the medial meniscus (DMM) mouse model. Results Increased circGNB1 expression was detected in HCs under oxidative and inflammatory stress and in the cartilage of older individuals. Mechanistically, circGNB1 sponged miR‐152‐3p and thus blocked its interaction with its downstream mRNA target, ring finger protein 219 (RNF219), which in turn stabilized caveolin‐1 (CAV1) by preventing its ubiquitination at the K47 residue. CircGNB1 inhibited IL‐10 signalling by antagonizing miR‐152‐3p‐mediated RNF219 and CAV1 inhibition. Consequently, circGNB1 overexpression promoted OA progression by enhancing catabolic factor expression and oxidative stress and by suppressing anabolic genes in vitro and in vivo. Furthermore, circGNB1 knockdown alleviated the severity of OA, whereas circGNB1 overexpression had the opposite effect in a DMM mouse model of OA. Conclusion CircGNB1 regulated oxidative stress and OA progression via the miR‐152‐3p/RNF219/CAV1 axis. Modulating circGNB1 could be an effective strategy for treating OA.

A table-top microdevice was introduced in this work to produce ultrasmall particles for drug delivery via inhalation. The design and operation are similar to that of spray-drying equipment used in industry, but the device itself is much smaller and more portable in size, simpler to operate and more economical. More importantly, the device enables more accurate control over particle size. Using Flavopiridol, an anti-inflammation medication, formulations have been developed to produce inhalable particles for pulmonary delivery. A solution containing the desired components forms droplets by passing through an array of micro-apertures that vibrate via a piezo-electrical driver. High-purity nitrogen gas was introduced and flew through the designed path, which included the funnel collection and cyclone chamber, and finally was pumped away. The gas carried and dried the micronized liquid droplets along the pathway, leading to the precipitation of dry solid microparticles. The formation of the cyclone was essential to assure the sufficient travel path length of the liquid droplets to allow drying. Synthesis parameters were optimized to produce microparticles, whose morphology, size, physio-chemical properties, and release profiles met the criteria for inhalation. Bioactivity assays have revealed a high degree of anti-inflammation. The above-mentioned approach enabled the production of inhalable particles in research laboratories in general, using the simple table-top microdevice. The microparticles enable the inhalable delivery of anti-inflammation medicine to the lungs, thus providing treatment for diseases such as pulmonary fibrosis and COVID-19.

Intervertebral disk degeneration (IVDD) is a spinal disk condition caused by an inflammatory response induced by various proinflammatory cytokines, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α. cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator and potential therapeutic target for many diseases, especially in regulating the activation of primary inflammatory response genes. Our study investigated a highly selective CDK9 inhibitor, atuveciclib, which protects nucleus pulposus (NP) cells from proinflammatory stimuli-induced catabolism. The effects of CDK9 inhibition were determined in human and rat NP cells treated with IL-1β in the presence or absence of atuveciclib or small interfering RNA target CDK9. Inhibition of CDK9 led to the attenuation of inflammatory response. In addition, rat intervertebral disk (IVD) explants were used to determine the role of CDK9 inhibition in extracellular matrix degradation. The rat IVDD model also proved that CDK9 inhibition attenuated IVDD, as validated using magnetic resonance imaging and immunohistochemistry. Taken together, CDK9 is a potential therapeutic target to prevent IVDD.

Bone resorption and homeostasis is carried out by osteoclasts, whose differentiation and activity are regulated by the RANK/RANKL axis. Our previous studies using a mouse model of joint injury show that joint trauma induces local inflammation followed by bone remodeling. The transcription factor cyclin-dependent kinase 9 (CDK9) is the major regulator of inflammation, as CDK9 inhibitor flavopiridol effectively suppress injury-induced inflammatory response. The objective of this study was to investigate the underlying mechanism through which flavopiridol regulates bone resorption. The effects of CDK9 inhibition, by the specific-inhibitor flavopiridol, on bone resorption were determined in vivo using two distinct and clinically relevant bone remodeling models. The first model involved titanium particle-induced acute osteolysis, and the second model was ovariectomy-induced chronic osteoporosis. The effects and mechanism of CDK9 inhibition on osteoclastogenesis were examined using in vitro culture of bone marrow macrophages (BMMs). Our results indicated that flavopiridol potently suppressed bone resorption in both in vivo bone-remodeling models. In addition, CDK9 inhibition suppressed in vitro osteoclastogenesis of BMM and reduced their expression of osteoclast-specific genes. Finally, we determined that flavopiridol suppressed RANKL signaling pathway via inhibition of p65 phosphorylation and nuclear translocation of NF-κB. Summary, CDK9 is a potential therapeutic target to prevent osteolysis and osteoporosis by flavopiridol treatment.

Introduction: Diffuse intrinsic pontine gliomas are associated with dismal survival outcomes. Conventional fractionation radiation to a dose of 60 Gy is the standard of treatment. This retrospective review aims to compare survival and toxicity outcomes of patients treated with conventional fractionation (CF) and hypofractionation (HF) radiotherapy., Materials and Methods: Treatment-naïve diffuse intrinsic pontine glioma patients undergoing radical radiation were analyzed. CF was delivered to a dose of 50-60 Gy in 25-30 fractions, while HF was delivered as 38-40 Gy in 12-15 fractions. All patients were planned via the volumetric modulated arc therapy (VMAT) technique., Results: A total of 64 patients were eligible for analysis. The median age of presentation was 10 years. Motor deficit was the most common presenting complaint in 51.6% of the patients, with a median symptom duration of 2 months. The pons was the most frequent site of disease epicenter in 71.8% of the patients. After a median follow-up of 9.45 months (range 0.23-72.63 months), 23 patients died, and 28 patients experienced disease progression. The unadjusted hazard ratio (HR) for death in patients treated with HF as compared to CF was 1.330 (95% CI 0.522-3.386) (p-value 0.550, by Cox regression analysis). The median OS for the entire cohort was 13.9 months, while it was 9.7 months (95% CI 5.65-13.74) and 15.1 months (95% CI 9.02-21.18) (p-value = 0.547) with CF and HF, respectively. On multivariate analysis, disease epicenter in the pons was the only significant factor associated with PFS. Hypofractionation was associated with a significantly higher aspiration rate and Ryle's tube requirement (p-value 0.027)., Conclusion: Hypofractionated radiation can be considered for diffuse intrinsic pontine glioma with optimum supportive care., Competing Interests: Declarations. Ethics approval: The work was done in accordance with the Declaration of Helsinki and was approved by institute ethics committee. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)