The biphasic role of the infrapatellar fat pad in osteoarthritis.

Osteoarthritis (OA) is a progressive degenerative disease resulting in joint deterioration. It is a whole organ disease characterized by cartilage degeneration and varying degrees of synovitis, involving pathological changes in all joint tissues, such as cartilage, subchondral bone, ligaments, meniscus, synovium, and infrapatellar fat pad (IPFP). IPFP is the largest adipose tissue structure in the knee joint and is composed of fat cells, immune cells and blood vessels. Moreover, IPFP is located close to the cartilage and bone surface so that it may reduce the impact of loading and absorb forces generated through the knee joint, and may have a protective role in joint health. IPFP has been shown to release various cytokines and adipokines that play pro-inflammatory and pro-catabolic roles in cartilage, promoting OA progression. Intra-articular injections of IPFP-derived mesenchymal stem cells and exosomes have been shown to reduce pain and prevent OA progression in patients with knee OA. Previous studies have shown that IPFP has a biphasic effect on OA progression. This article reviews the latest research progress of IPFP, discusses the role and mechanism of IPFP in OA, provide new intervention strategies for the treatment of OA. This article will also discuss the handling of IPFP during the procedure of total knee arthroplasty.

Lactate-upregulated ARG2 expression induces cellular senescence in fibroblast-like synoviocytes of osteoarthritis via activating the mTOR/S6K1 signaling pathway.

Cellular senescence was implicated in the pathogenesis of age-related diseases such as osteoarthritis (OA). Increasing evidence suggests that alterations in the OA joint microenvironment play a crucial role in the pathogenesis of OA. This study aims to establish a clear link between the impact of accumulated lactate on the senescence of fibroblast-like synoviocytes (FLS) within the OA microenvironment. OA models and models with intra-articular injection of lactate were established in rat models, histological analyses were performed. Human OA-FLS treated with lactate was analyzed by mRNA sequencing, senescence related experiments and underlying signaling pathway activation were comprehensively evaluated. This study confirmed that OA models and lactate-injection models exhibited higher synovitis scores. Enrichment analyses indicated dysregulated cell cycle and cellular senescence pathways in OA-FLS treated with lactate. Lactate significantly up-regulated arginase 2 (ARG2) expression and promoted OA-FLS senescence, including G1/S arrest, increased reactive oxygen species and ß-galactosidase production, high expression of senescence-associated secretory phenotype factors, which could be attenuated by siRNA-Arg2. The ARG2-mTOR/S6K1 axis was identified as a potential signaling for lactate-induced OA-FLS senescence, and activated mTOR/S6K1 signaling could be reduced by siRNA-Arg2, rapamycin (mTOR inhibitor), and LY294002 (PI3K inhibitor). Our study provides novel targets and insights for OA therapies.

Identification of diagnostic genes and drug prediction in metabolic syndrome-associated rheumatoid arthritis by integrated bioinformatics analysis, machine learning, and molecular docking.

Background: Interactions between the immune and metabolic systems may play a crucial role in the pathogenesis of metabolic syndrome-associated rheumatoid arthritis (MetS-RA). The purpose of this study was to discover candidate biomarkers for the diagnosis of RA patients who also had MetS. Methods: Three RA datasets and one MetS dataset were obtained from the Gene Expression Omnibus (GEO) database. Differential expression analysis, weighted gene co-expression network analysis (WGCNA), and machine learning algorithms including Least Absolute Shrinkage and Selection Operator (LASSO) regression and Random Forest (RF) were employed to identify hub genes in MetS-RA. Enrichment analysis was used to explore underlying common pathways between MetS and RA. Receiver operating characteristic curves were applied to assess the diagnostic performance of nomogram constructed based on hub genes. Protein-protein interaction, Connectivity Map (CMap) analyses, and molecular docking were utilized to predict the potential small molecule compounds for MetS-RA treatment. qRT-PCR was used to verify the expression of hub genes in fibroblast-like synoviocytes (FLS) of MetS-RA. The effects of small molecule compounds on the function of RA-FLS were evaluated by wound-healing assays and angiogenesis experiments. The CIBERSORT algorithm was used to explore immune cell infiltration in MetS and RA. Results: MetS-RA key genes were mainly enriched in immune cell-related signaling pathways and immune-related processes. Two hub genes (TYK2 and TRAF2) were selected as candidate biomarkers for developing nomogram with ideal diagnostic performance through machine learning and proved to have a high diagnostic value (area under the curve, TYK2, 0.92; TRAF2, 0.90). qRT-PCR results showed that the expression of TYK2 and TRAF2 in MetS-RA-FLS was significantly higher than that in non-MetS-RA-FLS (nMetS-RA-FLS). The combination of CMap analysis and molecular docking predicted camptothecin (CPT) as a potential drug for MetS-RA treatment. In vitro validation, CPT was observed to suppress the cell migration capacity and angiogenesis capacity of MetS-RA-FLS. Immune cell infiltration results revealed immune dysregulation in MetS and RA. Conclusion: Two hub genes were identified in MetS-RA, a nomogram for the diagnosis of RA and MetS was established based on them, and a potential therapeutic small molecule compound for MetS-RA was predicted, which offered a novel research perspective for future serum-based diagnosis and therapeutic intervention of MetS-RA.

Genetic control over biogenic crystal morphogenesis in zebrafish.

Organisms evolve mechanisms that regulate the properties of biogenic crystals to support a wide range of functions, from vision and camouflage to communication and thermal regulation. Yet, the mechanism underlying the formation of diverse intracellular crystals remains enigmatic. Here we unravel the biochemical control over crystal morphogenesis in zebrafish iridophores. We show that the chemical composition of the crystals determines their shape, particularly through the ratio between the nucleobases guanine and hypoxanthine. We reveal that these variations in composition are genetically controlled through tissue-specific expression of specialized paralogs, which exhibit remarkable substrate selectivity. This orchestrated combination grants the organism with the capacity to generate a broad spectrum of crystal morphologies. Overall, our findings suggest a mechanism for the morphological and functional diversity of biogenic crystals and may, thus, inspire the development of genetically designed biomaterials and medical therapeutics.

RETRACTED: Dong et al. Inhibition of SDF-1α/CXCR4 Signalling in Subchondral Bone Attenuates Post-Traumatic Osteoarthritis. Int. J. Mol. Sci. 2016, 17, 943.

The journal retracts the article "Inhibition of SDF-1α/CXCR4 Signalling in Subchondral Bone Attenuates Post-Traumatic Osteoarthritis" [...].

MetaboReport: from metabolomics data analysis to comprehensive reporting.

MOTIVATION: Metabolomics, as an essential tool in systems biology, is now widely accessible to researchers of all levels. Yet challenges remain in data analysis and result interpretation. To address these challenges, we introduced MetaboReport, a versatile and interactive web app that simplifies metabolomics experiment design, data preprocessing, exploration, statistical analysis, visualization, and reporting. RESULTS: MetaboReport produces a comprehensive HTML report, including project details, an introduction, interactive plots and tables, statistical results and an in-depth explanations and interpretation of the results. MetaboReport is particularly tailored for research labs and metabolomics core facilities that provide metabolomics services, allowing them to efficiently manage and document different metabolomics projects, and effectively report the metabolomics results to users. AVAILABILITY AND IMPLEMENTATION: MetaboReport is freely accessible on https://metaboreport.com, with source code available on GitHub (https://github.com/YonghuiDong/MetReport). Alternatively, users can install MetaboReport as a standalone desktop app (https://metaboreport.sourceforge.io).

Recent advances in the treatment of renal stones using flexible ureteroscopys.

Upper urinary tract stones are a common urological disease that can be treated by flexible ureteroscopy (FURS) through the natural urinary tract, in addition to extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy. The advantages of FURS are less trauma, faster recovery, and fewer complications, while its disadvantages include poor results of lithotripsy and stone extraction when dealing with larger stones, and prolonged operation time. Over the last two decades, the emergence of new technologies such as FURS combined with negative pressure suction, robot-assisted FURS, and artificially intelligent FURS, coupled with improvements in laser technology (the use of thulium fiber lasers and the invention of single-use flexible ureteroscopes (su-fURS) suitable for primary level application, have significantly increased the global adoption of FURS. This surge in usage holds a promising future in clinical application, benefiting a growing number of patients with renal calculi. Accompanied by changes in technical concepts and therapeutic modalities, the scope of indications for FURS is broadening, positioning it as a potential primary choice for urolithiasis treatment in the future. This review outlines the progress in employing FURS for the treatment of renal calculi in order to generate insights for further research.

Spatial Metabolomics Reveals the Multifaceted Nature of Lamprey Buccal Gland and Its Diverse Mechanisms for Blood-Feeding.

Lampreys are blood-sucking vampires in marine environments. From a survival perspective, it is expected that the lamprey buccal gland exhibits a repository of pharmacologically active components to modulate the host's homeostasis, inflammatory and immune responses. By analyzing the metabolic profiles of 14 different lamprey tissues, we show that two groups of metabolites in the buccal gland of lampreys, prostaglandins and the kynurenine pathway metabolites, can be injected into the host fish to assist lamprey blood feeding. Prostaglandins are well-known blood-sucking-associated metabolites that act as vasodilators and anticoagulants to maintain vascular homeostasis and are involved in inflammatory responses. The vasomotor reactivity test on catfish aortic ring showed that kynurenine can also relax the blood vessels of the host fish, thus improving the blood flow of the host fish at the bite site. Finally, a lamprey spatial metabolomics database ( https://www.lampreydb.com ) was constructed to assist studies using lampreys as animal model.

A complete prostaglandin pathway from synthesis to inactivation in the oral gland of the jawless vertebrate lamprey, Lethenteron camtschaticum.

Information on the prostaglandin pathway in lampreys is limited. Here, five genes related to the prostaglandin pathway from synthesis to inactivation, namely, phospholipase A2, cyclooxygenase-2, prostaglandin E synthase 3, prostaglandin D synthase, and 15-hydroxyprostaglandin dehydrogenase [NAD(+)], were screened and cloned from the lamprey, Lethenteron camtschaticum. Bioinformatic analysis showed that these lamprey genes are relatively conserved with teleost genes in domains, motifs, gene structure and 3D structure. Analysis of expression distribution of the genes in lamprey tissues revealed that a complete prostaglandin pathway from synthesis to inactivation exists in the oral gland of lamprey, especially the key gene of prostaglandin synthesis cyclooxygenase-2, which was highly expressed in the oral gland. Furthermore, cyclooxygenase-2 expression increased after LPS and Poly I:C stimulations. Using our established spatial metabolite database LampreyDB, six prostaglandin-related metabolites were screened from the oral gland of lamprey, four of which were highly expressed in the oral gland. This study provides new insights into prostaglandin synthesis and inactivation pathways in lamprey, thereby improving our understanding of the origin and evolution of the prostaglandin pathway and contributing to the recognition of lamprey regulatory mechanisms in development and immunity.

Stromal cell-derived factor-1α regulates chondrogenic differentiation via activation of the Wnt/ß-catenin pathway in mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSCs) have been applied to treat degenerative articular diseases, and stromal cell-derived factor-1α (SDF-1α) may enhance their therapeutic efficacy. However, the regulatory effects of SDF-1α on cartilage differentiation remain largely unknown. Identifying the specific regulatory effects of SDF-1α on MSCs will provide a useful target for the treatment of degenerative articular diseases. AIM: To explore the role and mechanism of SDF-1α in cartilage differentiation of MSCs and primary chondrocytes. METHODS: The expression level of C-X-C chemokine receptor 4 (CXCR4) in MSCs was assessed by immunofluorescence. MSCs treated with SDF-1α were stained for alkaline phosphatase (ALP) and with Alcian blue to observe differentiation. Western blot analysis was used to examine the expression of SRY-box transcription factor 9, aggrecan, collagen II, runt-related transcription factor 2, collagen X, and matrix metalloproteinase (MMP)13 in untreated MSCs, of aggrecan, collagen II, collagen X, and MMP13 in SDF-1α-treated primary chondrocytes, of glycogen synthase kinase 3ß (GSK3ß) p-GSK3ß and ß-catenin expression in SDF-1α-treated MSCs, and of aggrecan, collagen X, and MMP13 in SDF-1α-treated MSCs in the presence or absence of ICG-001 (SDF-1α inhibitor). RESULTS: Immunofluorescence showed CXCR4 expression in the membranes of MSCs. ALP stain was intensified in MSCs treated with SDF-1α for 14 d. The SDF-1α treatment promoted expression of collagen X and MMP13 during cartilage differentiation, whereas it had no effect on the expression of collagen II or aggrecan nor on the formation of cartilage matrix in MSCs. Further, those SDF-1α-mediated effects on MSCs were validated in primary chondrocytes. SDF-1α promoted the expression of p-GSK3ß and ß-catenin in MSCs. And, finally, inhibition of this pathway by ICG-001 (5 µmol/L) neutralized the SDF-1α-mediated up-regulation of collagen X and MMP13 expression in MSCs. CONCLUSION: SDF-1α may promote hypertrophic cartilage differentiation in MSCs by activating the Wnt/ß-catenin pathway. These findings provide further evidence for the use of MSCs and SDF-1α in the treatment of cartilage degeneration and osteoarthritis.

Isobavachalcone ameliorates the progression of osteoarthritis by suppressing NF-κB signaling pathway.

Isobavachalcone (IBC), an active component isolated from Psoralea corylifolia L., has been used extensively to treat a wide range of inflammation-associated diseases. However, little is known regarding the potential effect of IBC in the treatment of osteoarthritis (OA). The purpose of this research was to investigate the potential therapeutic effectsof IBC on OA by performingin vitroand in vivo experiments. Meanwhile, the underlying mechanism responsibles for that effect was also explored. Primary rat chondrocytes were isolated from the knee cartilage, and then pretreated with various concentrations of IBC followed by stimulation with or without LPS (1 µg/ml) for the indicated times. In vitro, the expression levels of iNOS, COX-2, MMP3, MMP13, ADAMTS5, aggrecan, and collagen II were determined by qRT-PCR, western blot, and immunofluorescence staining. In addition, western blot analysis and immunofluorescence were used to assess alterations to the NF-κB signaling pathway. In vivo, an ACLT-induced rat OA model was established in order to determine the protective effect of IBC. The results showed that IBC treatment inhibited the upregulation of inflammatory factors such as iNOS and COX-2 in response to LPS stimulation. Moreover, IBC significantly suppressed the expression of MMP-3, MMP-13, and ADAMTS5 induced by LPS in a dose-dependent manner. Furthermore, the LPS-induced reduction of collagen II and aggrecan was reversed by IBC. Mechanistically, IBC significantly decreased LPS-induced p65 phosphorylation and IκBα degradation as well as suppressed nuclear translocation of p65 in rat chondrocytes as evidenced by western blot analysis and immunofluorescence staining, indicating that IBC effectively inhibited the LPS-induced activation of the NF-κB pathway. In vivo, IBC treatment prevented cartilage degeneration in the ACLT-induced rat model. In summary, our results suggest that IBC may be able to act as a promising therapeutic drug for treating OA.

PICA: Pixel Intensity Correlation Analysis for Deconvolution and Metabolite Identification in Mass Spectrometry Imaging.

In-source fragmentation (ISF) is a naturally occurring phenomenon in various ion sources including soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI). It has traditionally been minimized as it makes the dataset more complex and often leads to mis-annotation of metabolites. Here, we introduce an approach termed PICA (for pixel intensity correlation analysis) that takes advantage of ISF in MALDI imaging to increase confidence in metabolite identification. In PICA, the extraction and association of in-source fragments to their precursor ion results in "pseudo-MS/MS spectra" that can be used for identification. We examined PICA using three different datasets, two of which were published previously and included validated metabolites annotation. We show that highly colocalized ions possessing Pearson correlation coefficient (PCC) ≥ 0.9 for a given precursor ion are mainly its in-source fragments, natural isotopes, adduct ions, or multimers. These ions provide rich information for their precursor ion identification. In addition, our results show that moderately colocalized ions (PCC < 0.9) may be structurally related to the precursor ion, which allows for the identification of unknown metabolites through known ones. Finally, we propose three strategies to reduce the total computation time for PICA in MALDI imaging. To conclude, PICA provides an efficient approach to extract and group ions stemming from the same metabolites in MALDI imaging and thus allows for high-confidence metabolite identification.

Saliva metabolome alterations after acute stress.

Major stress has systemic effects on the body that can have adverse consequences for physical and mental health. However, the molecular basis of these damaging effects remains incompletely understood. Here we use a longitudinal approach to characterise the acute systemic impact of major psychological stress in a pig model. We perform untargeted metabolomics on non-invasively obtained saliva samples from pigs before and 24 h after transfer to the novel physical and social environment of a slaughterhouse. The main molecular changes occurring include decreases in amino acids, B-vitamins, and amino acid-derived metabolites synthesized in B-vitamin-dependent reactions, as well as yet-unidentified metabolite features. Decreased levels of several of the identified metabolites are implicated in the pathology of human psychological disorders and neurodegenerative disease, suggesting a possible neuroprotective function. Our results provide a fingerprint of the acute effect of psychological stress on the metabolome and suggest candidate biomarkers with potential roles in stress-related disorders.

Down-Regulation of Ubiquitin-Specific Peptidase 9X Inhibited Proliferation, Migration and Invasion of Osteosarcoma via ERK1/2 and PI3K/Akt Signaling Pathways.

Ubiquitin-specific peptidase 9X (USP9X) has been reported to be closely associated with the formation and progression of a variety of malignant tumors. However, the mechanism by which USP9X is involved in osteosarcoma and development has not been clearly studied. This work aimed to probe the influence of USP9X on osteosarcoma cell proliferation, migration and invasion. This study recruited sixty-seven patients with histologically definited osteosarcoma. Osteosarcoma samples and cell-line were used to reflect the expression level of USP9X. Analysis of cell proliferation by thiazolium blue (MTT) assays. Transwell experiments and wound healing were used to verify cell migration and invasion capabilities. The effect of USP9X was investigated through in vivo experiments. USP9X-related pathway proteins were detected by Western blot and quantitative real-time PCR (qRT-PCR). The expression of USP9X in osteosarcoma was higher than that in adjacent tissues. The overall survival of patients with USP9X-negative patients was better than that of patients with USP9X-positive. The growth of osteosarcoma cells in vivo and in vitro was inhibited by USP9X inhibitor. Cell migration and invasion were significantly inhibited by down-regulation of USP9X. USP9X was involved in extracellular signal-regulated kinase 1/2 (ERK1/2) and phosphatidylinositol-3-kinases/protein-serine-threonine kinase (PI3K/Akt) pathway in osteosarcoma cells. Proliferation, migration and invasion of osteosarcoma cells were inhibited by down-regulation of USP9X, and were related to the ERK1/2 and PI3K/Akt signaling pathways, therefore, it might probably become a new target for the prevention and treatment of osteosarcoma.

Therapeutic potential of nanotechnology-based approaches in osteoarthritis.

Osteoarthritis (OA) is a multifactorial disease that affects the entire joint, often resulting in severe pain, disability, psychological distress, and a lower quality of life. Patient self-management is emphasized in OA clinical recommendations. Currently, the clinical treatment of OA mainly focuses on pain relief and the improvement of joint function, with few options for regenerating degenerative cartilage or slowing the progression of OA. Therefore, we first reviewed the current treatment of OA, and then summarized the research advances of nanotechnology in OA treatment, including nano drug delivery systems for small molecule drugs, nucleic acids and proteins, nano-scaffolds for cartilage regeneration, and nanoparticle lubricants. Finally, we discussed the opportunities and potential challenges of nanotechnology in OA treatment.

Regulatory Role of N6-Methyladenosine (m6A) Modification in Osteoarthritis.

Osteoarthritis (OA) is the most common joint disease, usually occurring in middle-aged and elderly people. However, current treatment for OA in its early stages is ineffective, and drug therapy is often ineffective in slowing the progression of the disease. In fact, a deeper understanding of the underlying molecular mechanisms of OA could help us to better develop effective therapeutic measures. N6-methyladenosine (m6A) is a methylation that occurs at the adenosine N6-position, which is the most common internal modification on eukaryotic mRNAs. The role and mechanisms of m6A in mammalian gene regulation have been extensively studied. The "Writer", "eraser", and "reader" proteins are key proteins involved in the dynamic regulation of m6A modifications. Recent studies on post-transcriptional regulation alone have shown that m6a modification has an important role in the development of OA. This paper summarizes the specific regulatory processes of M6A in disease and reviews the role of m6A in OA, describing its pathophysiological role and molecular mechanisms, as well as its future research trends and potential clinical applications in OA.

The Potential Roles of Dietary Anthocyanins in Inhibiting Vascular Endothelial Cell Senescence and Preventing Cardiovascular Diseases.

Cardiovascular disease (CVD) is a group of diseases affecting the heart and blood vessels and is the leading cause of morbidity and mortality worldwide. Increasingly more evidence has shown that the senescence of vascular endothelial cells is the key to endothelial dysfunction and cardiovascular diseases. Anthocyanin is a type of water-soluble polyphenol pigment and secondary metabolite of plant-based food widely existing in fruits and vegetables. The gut microbiome is involved in the metabolism of anthocyanins and mediates the biological activities of anthocyanins and their metabolites, while anthocyanins also regulate the growth of specific bacteria in the microbiota and promote the proliferation of healthy anaerobic flora. Accumulating studies have shown that anthocyanins have antioxidant, anti-inflammatory, and anti-aging effects. Many animal and in vitro experiments have also proven that anthocyanins have protective effects on cardiovascular-disease-related dysfunction. However, the molecular mechanism of anthocyanin in eliminating aging endothelial cells and preventing cardiovascular diseases is very complex and is not fully understood. In this systematic review, we summarize the metabolism and activities of anthocyanins, as well as their effects on scavenging senescent cells and cardioprotection.

The metabolic and proteomic repertoires of periderm tissue in skin of the reticulated Sikkim cucumber fruit.

Suberized and/or lignified (i.e. lignosuberized) periderm tissue appears often on surface of fleshy fruit skin by mechanical damage caused following environmental cues or developmental programs. The mechanisms underlying lignosuberization remain largely unknown to date. Here, we combined an assortment of microscopical techniques with an integrative multi-omics approach comprising proteomics, metabolomics and lipidomics to identify novel molecular components involved in fruit skin lignosuberization. We chose to investigate the corky Sikkim cucumber (Cucumis sativus var. sikkimensis) fruit. During development, the skin of this unique species undergoes massive cracking and is coated with a thick corky layer, making it an excellent model system for revealing fundamental cellular machineries involved in fruit skin lignosuberization. The large-scale data generated provides a significant source for the field of skin periderm tissue formation in fleshy fruit and suberin metabolism.

TMT-based quantitative proteomics reveals protein biomarkers from cultured Pacific abalone (Haliotis discus hannai) in different regions.

Due to latitude, the growth cycle of abalone in southern China is significantly lower than that in the northern regions. Therefore, it often occurs merchants use southern abalone to disguise as northern abalone. This study aims to explore the differences in the muscle proteome of Pacific abalone (Haliotis discus hannai) in different regions. A total of 1,569 proteins were detected and 729 proteins were identified as differential abundance proteins (DAPs) in Haliotis discus hannai cultured in Northern (Liaoning Province) and Southern (Fujian Province) China. Bioinformatics analysis revealed and Western blot verified that fatty acid synthase, troponin I, calpain small subunit 1, and myosin light chain 6 are candidate biomarkers for abalone cultured in different regions. This study provides a deeper understanding of how to distinguish which region abalone is harvested from to improve abalone quality controls, and prevent food fraud.

Image to insight: exploring natural products through mass spectrometry imaging.

Covering: 2017 to 2022Mass spectrometry imaging (MSI) has become a mature molecular imaging technique that is well-matched for natural product (NP) discovery. Here we present a brief overview of MSI, followed by a thorough discussion of different MSI applications in NP research. This review will mainly focus on the recent progress of MSI in plants and microorganisms as they are the main producers of NPs. Specifically, the opportunity and potential of combining MSI with other imaging modalities and stable isotope labeling are discussed. Throughout, we focus on both the strengths and weaknesses of MSI, with an eye on future improvements that are necessary for the progression of MSI toward routine NP studies. Finally, we discuss new areas of research, future perspectives, and the overall direction that the field may take in the years to come.