Cyclin-Dependent Kinase 9 (CDK9) Inhibitor Atuveciclib Suppresses Intervertebral Disk Degeneration via the Inhibition of the NF-κB Signaling Pathway

Long noncoding RNA small nucleolar RNA host gene 5 facilitates neuropathic pain in spinal nerve injury by promoting SCN9A expression via CDK9

This study aims to explore the functions and mechanisms of long noncoding RNA small nucleolar RNA host gene 5 (SNHG5) in chronic constriction injury (CCI)-induced neuropathic pain (NP). An NP rat model was established using the CCI method and the NP severity was evaluated by paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The expression of SNHG5, CDK9, and SCN9A was quantified in rat dorsal root ganglion, in addition to the detections of apoptosis, pathological changes, neuron number, and the co-localization of Nav1.7 and cleaved caspase-3 with NeuN. In ND7/23 cells, the apoptosis and lactate dehydrogenase concentration were assessed, as well as the relationship between SNHG5, CDK9, and SCN9A. In the dorsal root ganglion of CCI-treated rats, SNHG5 and SCN9A were upregulated and downregulation of SNHG5 suppressed SCN9A expression, increased the PWT and PWL, blocked neuroinflammation and neuronal apoptosis, and alleviated NP. Mechanistically, SNHG5 recruited CDK9 to enhance SCN9A-encoded Nav1.7 expression and promoted peripheral neuronal apoptosis and injury. In addition, SCN9A overexpression nullified the alleviative effects of SNHG5 deficiency on NP and neuron loss in CCI rats. In conclusion, SNHG5 promotes SCN9A-encoded Nav1.7 expression by recruiting CDK9, thereby facilitating neuron loss and NP after spinal nerve injury, which may offer a promising target for the management of NP.

Production of Inhalable Ultra-Small Particles for Delivery of Anti-Inflammation Medicine via a Table-Top Microdevice

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.

Tissue Renin-Angiotensin System (tRAS) Induce Intervertebral Disc Degeneration by Activating Oxidative Stress and Inflammatory Reaction

Lumbar intervertebral disc degeneration (IDD) has been the major contributor to low back pain (LBP). IDD is an chronic inflammation process, with the activation of plentiful inflammation-related cytokines and ECM degradation-related enzymes. In the past few years, hypertension has been reported to correlate with LBP. In addition, the local tissue renin-angiotensin system (tRAS) has been identified in multiple tissues, including the spinal cord, skin, kidney, heart, and bone. Recently, tRAS has also been established in both bovine and human intervertebral disc tissues, especially in the degenerated disc tissue. However, the exact of tRAS and IDD remains unknown. In this present study, proteomic analysis, molecular biology analysis, and animal model were all used. Firstly, we revealed that tRAS was excessively activated in the human degenerated intervertebral disc tissue via proteomic analysis and molecular biology analysis. Then, in vitro experiment suggested that Ang II could decrease the cell viability of human NP cells and promote NP cell apoptosis, senescence, oxidative stress, and NLRP3 activation in human NP cells. In addition, Ang II could also trigger degeneration and fibrosis phenotype in human NP cells. Finally, the animal model demonstrated that the local activated ACE/Ang II axis in the NP tissue could accelerate IDD in aging spontaneously hypertensive rats (SHR). Collectively, the degenerated intervertebral disc tissue showed excessively activated tRAS, and local activated tRAS could induce NP cell senescence, apoptosis, oxidative stress, and inflammatory reaction to promote IDD. These biological effects of Ang II on human NP cells may provide novel insight into further treatment of IDD.