BACKGROUND: Intervertebral disc degeneration (IDD) naturally occurs during the aging process. Its occurrence is closely related to chronic inflammation; however, the causal relationship between them is controversial. This study aimed to investigate if inflammation would promote IDD incidence and explore the underlying mechanism. METHODS: A chronic inflammation mouse model was established by intraperitoneal injection of lipopolysaccharide (LPS). Enzyme-linked immunosorbent assay was performed to determine proinflammatory cytokines in serum. Histological staining was used to evaluate the degeneration of IVDs. Immunoblots and RT-qPCR analyses were performed to measure protein and mRNA expression levels. Immunoprecipitation, mass spectrometry, and co-immunoprecipitation assays were used to determine the assembly of protein complex. RESULTS: We found that an inflammatory microenvironment activated p38 kinase, which phosphorylated the Runx2 transcription factor at the Ser28 site. The phosphorylated Runx2 (pRunx2) then recruited a deubiquitinase, ubiquitin-specific peptidase 24 (USP24), which stabilized pRunx2 and protected it from ubiquitin-dependent proteasomal degradation. The stabilized pRunx2 recruited histone acetyltransferase p300 and nuclear receptor coactivator 3 (NCOA3) to assemble a complex. This NCOA3-p300-pRunx2 complex then transactivated the expression of 13 ADAMTS (a disintegrin and metalloproteinase with thrombospondin motif) genes, thereby promoting the degradation of extracellular matrix (ECM) in intervertebral discs (IVDs) and causing IDD. Administration of either a p38 inhibitor (doramapimod), a NCOA3 inhibitor (bufalin), or a p300 inhibitor (EML425) significantly decreased the expression of the 13 ADAMTS genes and slowed the degeneration of IVDs. CONCLUSION: In summary, our results demonstrate that USP24 protects pRunx2 from proteasomal degradation under chronic inflammation conditions, enabling pRunx2 to transactivate ADAMTS genes and degrade ECM. Our findings provide direct evidence that chronic inflammation triggers IDD and offer a therapeutic strategy for retarding IDD in patients with chronic inflammation.

LncRNA PSMA3-AS1 functions as an oncogene in several cancers, including ovarian cancer, lung cancer, and colorectal cancer. However, its role in gastric cancer (GC) progression remains unclear. In this study, the levels of PSMA3-AS1, miR-329-3p, and aldolase A (ALDOA) in 20 paired human GC tissues and adjacent nontumorous tissues were measured by real-time PCR. GC cells were transfected with recombinant plasmid carrying full-length PSMA3-AS1 or shRNA targeting PSMA3-AS1. The stable transfectants were selected by G418. Then, the effects of PSMA3-AS1 knockdown or overexpression on GC progression in vitro and in vivo were evaluated. The results showed that PSMA3-AS1 was highly expressed in human GC tissues. Stable knockdown of PSMA3-AS1 significantly restrained proliferation/migration/invasion, enhanced cell apoptosis, and induced oxidative stress in vitro. Tumor growth and matrix metalloproteinase expression in tumor tissues were markedly inhibited, while oxidative stress was enhanced in nude mice after stable PSMA3-AS1 knockdown. Additionally, PSMA3-AS1 negatively regulated miR-329-3p while positively regulated ALDOA expression. MiR-329-3p directly targeted ALDOA-3'UTR. Interestingly, miR-329-3p knockdown or ALDOA overexpression partially attenuated the tumor-suppressive effects of PSMA3-AS1 knockdown. Conversely, PSMA3-AS1 overexpression exhibited the opposite effects. PSMA3-AS1 promoted GC progression by regulating the miR-329-3p/ALDOA axis. PSMA3-AS1 might serve as a promising and effective target for GC treatment.

BACKGROUND: Volumetric Muscle Loss (VML), resulting from severe trauma or surgical ablation, is a pathological condition preventing myofibers regeneration, since skeletal muscle owns the remarkable ability to restore tissue damage, but only when limited in size. The current surgical therapies employed in the treatment of this pathology, which particularly affects military personnel, do not yet provide satisfactory results. For this reason, more innovative approaches must be sought, specifically skeletal muscle tissue engineering seems to highlight promising results obtained from preclinical studies in VML mouse model. Despite the great results obtained in rodents, translation into human needs a comparable animal model in terms of size, in order to validate the efficacy of the tissue engineering approach reconstructing larger muscle mass (human-like). In this work we aim to demonstrate the validity of a porcine model, that has underwent a surgical ablation of a large muscle area, as a VML damage model. RESULTS: For this purpose, morphological, ultrasound, histological and fluorescence analyses were carried out on the scar tissue formed following the surgical ablation of the peroneus tertius muscle of Sus scrofa domesticus commonly called mini-pig. In particular, the replenishment of the damaged area, the macrophage infiltration and the vascularization at different time-points were evaluated up to the harvesting of the scar upon six months. CONCLUSION: Here we demonstrated that following VML damage, there is an extremely poor regenerative process in the swine muscle tissue, while the formation of fibrotic, scar tissue occurs. The analyses performed up to 180 days after the injury revealed the development of a stable, structured and cellularized tissue, provided with vessels and extracellular matrix acquiring the status of granulation tissue like in human.

Duchenne muscular dystrophy (DMD) is a severe form of muscular dystrophy caused by mutations in the dystrophin gene. We characterized which isoforms of dystrophin were expressed by human induced pluripotent stem cell (hiPSC)-derived cardiac fibroblasts obtained from control and DMD patients. Distinct dystrophin isoforms were observed; however, highest molecular weight isoform was absent in DMD patients carrying exon deletions or mutations in the dystrophin gene. The loss of the full-length dystrophin isoform in hiPSC-derived cardiac fibroblasts from DMD patients resulted in deficient formation of actin microfilaments and a metabolic switch from mitochondrial oxidation to glycolysis. The DMD hiPSC-derived cardiac fibroblasts exhibited a dysregulated mitochondria network and reduced mitochondrial respiration, with enhanced compensatory glycolysis to sustain cellular ATP production. This metabolic remodeling was associated with an exacerbated myofibroblast phenotype and increased fibroblast activation in response to pro fibrotic challenges. As cardiac fibrosis is a critical pathological feature of the DMD heart, the myofibroblast phenotype induced by the absence of dystrophin may contribute to deterioration in cardiac function. Our study highlights the relationship between cytoskeletal dynamics, metabolism of the cell and myofibroblast differentiation and provides a new mechanism by which inactivation of dystrophin in non-cardiomyocyte cells may increase the severity of cardiopathy.

Natural ageing of organisms and corresponding age-related diseases result mainly from stem cell ageing and "inflammaging". Mesenchymal stem cells (MSCs) exhibit very high immune-regulating capacity and are promising candidates for immune-related disease treatment. However, the effect of MSC application is not satisfactory for some patients, especially in elderly individuals. With ageing, MSCs undergo many changes, including altered cell population reduction and differentiation ability, reduced migratory and homing capacity and, most important, defective immunosuppression. It is necessary to explore the relationship between the "inflammaging" and aged MSCs to prevent age-related diseases and increase the therapeutic effects of MSCs. In this review, we discuss changes in naturally ageing MSCs mainly from an inflammation perspective and propose some ideas for rejuvenating aged MSCs in future treatments.

BACKGROUND: Previously, we identified an oncogenic splicing variant of DOCK5 in head and neck squamous cell carcinoma (HNSCC); however, the mechanism for the generation of this specific DOCK5 variant remains unknown. This study aims to explore the potential spliceosome genes involved in the production of the DOCK5 variant and validate its role in regulating the progression of HNSCC. METHODS: The differentially expressed spliceosome genes involved in the DOCK5 variant were analysed in The Cancer Genome Atlas (TCGA), and the correlation between the DOCK5 variant and the potential spliceosome gene PHF5A was verified by qRT-PCR. The expression of PHF5A was detected in HNSCC cells, TCGA data and a separate primary tumour cohort. The functional role of PHF5A was examined using CCK-8, colony formation, cell scratch and Transwell invasion assays in vitro and validated in vivo in xenograft models of HNSCC. Western blot analysis was used to explore the potential mechanism of PHF5A in HNSCC. RESULTS: PHF5A was one of the top upregulated spliceosome genes in TCGA HNSCC samples with highly expressed DOCK5 variants. Knockdown or overexpression of PHF5A in HNSCC cells correspondingly altered the level of the DOCK5 variant. PHF5A was highly expressed in tumour cells and tissues and correlated with a worse prognosis of HNSCC. Loss- and gain-of-function experiments demonstrated that PHF5A could promote the proliferation, migration and invasion of HNSCC cells in vitro and in vivo. Moreover, PHF5A inhibition reversed the oncogenic effect of the DOCK5 variant in HNSCC. Western blot analysis showed that PHF5A activated the p38 MAPK pathway, and inhibition of p38 MAPK further reversed the effect of PHF5A on the proliferation, migration and invasion of HNSCC cells. CONCLUSION: PHF5A regulates the alternative splicing of DOCK5 to promote HNSCC progression through p38 MAPK activation, which provides potential therapeutic implications for HNSCC patients.

BACKGROUND: Prostate cancer remains one of the deadliest neoplasms in developed countries. Identification of new molecular markers that predict the onset and progression of the disease could improve its clinical management. Low miR-145-5p expression is consistently found in primary tumors and metastases, but the regulatory mechanisms governing its functions remain largely unknown. METHODS: Bioinformatics analysis was conducted to identify [1] a set of novel potential competing endogenous lncRNAs for sponging of miRNA-145-5p in prostate cancer and [2] miR-145-5p and other EMT-related miRNAs response elements in lnc-ZNF30-3. Quantification of miR-145-5p, lnc-ZNF30-3, and TWIST1 expression levels in tumor tissues in RNA sequencing datasets of our and TCGA PRAD cohorts revealed a correlation with clinical outcome of prostate cancer patients. Biochemical and cell biology approaches, such as RNA pull-down, western blot, immunostaining, and wound healing assays were used for evaluation of the impact of TWIST1/miR-145/ lnc-ZNF30-3 interactions in prostate cancer cells altered in miRNA and lncRNA expression. RESULTS: We identified a few potential lncRNA sponges of miR-145-5p, including lnc-ZNF30-3. It contains five response elements for miR-145-5p, but also other miRNAs targeting EMT transcription factors. Lnc-ZNF30-3 is significantly upregulated in prostate cancer cell lines and tumor tissues, and its high expression is correlated with poor patient prognosis. We demonstrated that lnc-ZNF30-3 is associated with AGO2 and specifically interacts with the miR-145-5p seed region. Knockdown of lnc-ZNF30-3 results in decreased migration of prostate cancer cells and downregulation of EMT drivers such as TWIST1 and ZEB1 at both the RNA and protein levels. These phenotypic and molecular features of lnc-ZNF30-3-depleted cells are partially rescued by miR-145-5p inhibition. CONCLUSIONS: Collectively, our results point to lnc-ZNF30-3 as a novel competing endogenous lncRNA for miR-145-5p and other miRNAs that target TWIST1 as well as other EMT transcription factors. Prostate cancer patients with high lncRNA expression in primary tumors show lower survival rate suggesting that lnc-ZNF30-3 may contribute to prostate cancer progression and metastasis.