Modulation of αVβ6 integrin in osteoarthritis-related synovitis and the interaction with VTN(381-397 a.a.) competing for TGF-β1 activation

Towards clinical translation of urinary vitronectin for non-invasive detection and monitoring of renal fibrosis in kidney transplant patients

BACKGROUND

Interstitial fibrosis and tubular atrophy (IFTA) is a critical factor in the prognosis of kidney health. Currently, IFTA quantitation in kidney biopsy samples is crucial for diagnosis and assessing disease severity, but the available non-invasive biomarkers are not satisfactory. Proteomic studies identified urinary vitronectin (VTN) as a potential biomarker for kidney fibrosis. As mass spectrometry techniques are not practical for use in clinical settings, we tested whether evaluation of urinary VTN levels through enzyme-linked immunosorbent assay (ELISA) can help monitor fibrotic changes in kidney transplant recipients and prove the clinical viability of the assay.

METHODS

A total of 58 kidney transplant (KTx) patients who underwent renal biopsy were included in the study. Patients were categorized into two groups referred as no fibrosis (0%) or with fibrosis (≥ 5%) based on their histological findings. In a subsequent/follow-up analysis, the time elapsed from transplantation was also considered. The urinary levels of VTN were measured using ELISA.

RESULTS

VTN (p = 0.0180) and VTN normalized by urinary creatinine levels (p = 0.0037), were significantly increased in patients with fibrotic grafts. When focusing on patients with long-term grafts (> 3 years from transplantation, n = 36), VTN exhibited superior potential in identifying fibrotic grafts compared to albuminuria (VTN p = 0.0040 vs. albuminuria p = 0.0132). Importantly, in this group, while albuminuria correctly identified 71% of fibrotic patients, the combination of VTN plus albuminuria correctly classified 89% of fibrotic grafts detected by renal biopsy.

CONCLUSIONS

VTN has emerged as a valid indicator of renal fibrosis. Of interest, urinary levels of VTN in combination with conventional clinical parameters (such as albuminuria) significantly improved the non-invasive detection of renal fibrosis in kidney transplant patients.

Whole-genome scan for selection signature associated with temperature adaptation in Iranian sheep breeds

The present study aimed to identify the selection signature associated with temperature adaptation in Iranian sheep breeds raised in cold and hot environments. The Illumina HD ovine SNP600K BeadChip genomic arrays were utilized to analyze 114 animals from eight Iranian sheep breeds, namely Ghezel, Afshari, Shall, Sanjabi, Lori-Bakhtiari, Karakul, Kermani, and Balochi. All animals were classified into two groups: cold-weather breeds and hot-weather breeds, based on the environments to which they are adapted and the regions where they have been raised for many years. The unbiased FST (Theta) and hapFLK tests were used to identify the selection signatures. The results revealed five genomic regions on chromosomes 2, 10, 11, 13, and 14 using the FST test, and three genomic regions on chromosomes 10, 14, and 15 using the hapFLK test to be under selection in cold and hot groups. Further exploration of these genomic regions revealed that most of these regions overlapped with genes previously identified to affect cold and heat stress, nervous system function, cell division and gene expression, skin growth and development, embryo and skeletal development, adaptation to hypoxia conditions, and the immune system. These regions overlapped with QTLs that had previously been identified as being associated with various important economic traits, such as body weight, skin color, and horn characteristics. The gene ontology and gene network analyses revealed significant pathways and networks that distinguished Iranian cold and hot climates sheep breeds from each other. We identified positively selected genomic regions in Iranian sheep associated with pathways related to cell division, biological processes, cellular responses to calcium ions, metal ions and inorganic substances. This study represents the initial effort to identify selective sweeps linked to temperature adaptation in Iranian indigenous sheep breeds. It may provide valuable insights into the genomic regions involved in climate adaptation in sheep.

Integrin signalling in joint development, homeostasis and osteoarthritis

Integrins are key regulators of cell-matrix interactions during joint development and joint tissue homeostasis, as well as in the development of osteoarthritis (OA). The signalling cascades initiated by the interactions of integrins with a complex network of extracellular matrix (ECM) components and intracellular adaptor proteins orchestrate cellular responses necessary for maintaining joint tissue integrity. Dysregulated integrin signalling, triggered by matrix degradation products such as matrikines, disrupts this delicate balance, tipping the scales towards an environment conducive to OA pathogenesis. The interplay between integrin signalling and growth factor pathways further underscores the multifaceted nature of OA. Moreover, emerging insights into the role of endocytic trafficking in regulating integrin signalling add a new layer of complexity to the understanding of OA development. To harness the therapeutic potential of targeting integrins for mitigation of OA, comprehensive understanding of their molecular mechanisms across joint tissues is imperative. Ultimately, deciphering the complexities of integrin signalling will advance the ability to treat OA and alleviate its global burden.

Fibrotic pathways and fibroblast-like synoviocyte phenotypes in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis, characterized by osteophyte formation, cartilage degradation, and structural and cellular alterations of the synovial membrane. Activated fibroblast-like synoviocytes (FLS) of the synovial membrane have been identified as key drivers, secreting humoral mediators that maintain inflammatory processes, proteases that cause cartilage and bone destruction, and factors that drive fibrotic processes. In normal tissue repair, fibrotic processes are terminated after the damage has been repaired. In fibrosis, tissue remodeling and wound healing are exaggerated and prolonged. Various stressors, including aging, joint instability, and inflammation, lead to structural damage of the joint and micro lesions within the synovial tissue. One result is the reduced production of synovial fluid (lubricants), which reduces the lubricity of the cartilage areas, leading to cartilage damage. In the synovial tissue, a wound-healing cascade is initiated by activating macrophages, Th2 cells, and FLS. The latter can be divided into two major populations. The destructive thymocyte differentiation antigen (THY)1─ phenotype is restricted to the synovial lining layer. In contrast, the THY1+ phenotype of the sublining layer is classified as an invasive one with immune effector function driving synovitis. The exact mechanisms involved in the transition of fibroblasts into a myofibroblast-like phenotype that drives fibrosis remain unclear. The review provides an overview of the phenotypes and spatial distribution of FLS in the synovial membrane of OA, describes the mechanisms of fibroblast into myofibroblast activation, and the metabolic alterations of myofibroblast-like cells.

Exploring the role of ITGB6: fibrosis, cancer, and other diseases

Integrin β6 (ITGB6), a member of the integrin family of proteins, is only present in epithelial tissues and frequently associates with integrin subunit αv to form transmembrane heterodimers named integrin αvβ6. Importantly, ITGB6 determines αvβ6 expression and availability. In addition to being engaged in organ fibrosis, ITGB6 is also directly linked to the emergence of cancer, periodontitis, and several potential genetic diseases. Therefore, it is of great significance to study the molecular-biological mechanism of ITGB6, which could provide novel insights for future clinical diagnosis and therapy. This review introduces the structure, distribution, and biological function of ITGB6. This review also expounds on ITGB6-related diseases, detailing the known biological effects of ITGB6.

Fibrocyte Phenotype of ENTPD1+CD55+ Cells and Its Association with Pain in Osteoarthritic Synovium

Osteoarthritis (OA) is a prevalent degenerative joint disorder characterized by cartilage erosion, structural changes, and inflammation. Synovial fibroblasts play a crucial role in OA pathophysiology, with abnormal fibroblastic cells contributing significantly to joint pathology. Fibrocytes, expressing markers of both hematopoietic and stromal cells, are implicated in inflammation and fibrosis, yet their marker and role in OA remain unclear. ENTPD1, an ectonucleotidase involved in purinergic signaling and expressed in specific fibroblasts in fibrotic conditions, led us to speculate that ENTPD1 plays a role in OA pathology by being expressed in fibrocytes. This study aimed to investigate the phenotype of ENTPD1+CD55+ and ENTPD1-CD55+ synovial fibroblasts in OA patients. Proteomic analysis revealed a distinct molecular profile in ENTPD1+CD55+ cells, including the upregulation of fibrocyte markers and extracellular matrix-related proteins. Pathway analysis suggested shared mechanisms between OA and rheumatoid arthritis. Correlation analysis revealed an association between ENTPD1+CD55+ fibrocytes and resting pain in OA. These findings highlight the potential involvement of ENTPD1 in OA pain and suggest avenues for targeted therapeutic strategies. Further research is needed to elucidate the underlying molecular mechanisms and validate potential therapeutic targets.

Role of transforming growth factor-β in peripheral nerve regeneration

Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits. Unlike in the central nervous system, damaged axons in peripheral nerves can be induced to regenerate in response to intrinsic cues after reprogramming or in a growth-promoting microenvironment created by Schwann cells. However, axon regeneration and repair do not automatically result in the restoration of function, which is the ultimate therapeutic goal but also a major clinical challenge. Transforming growth factor (TGF) is a multifunctional cytokine that regulates various biological processes including tissue repair, embryo development, and cell growth and differentiation. There is accumulating evidence that TGF-β family proteins participate in peripheral nerve repair through various factors and signaling pathways by regulating the growth and transformation of Schwann cells; recruiting specific immune cells; controlling the permeability of the blood-nerve barrier, thereby stimulating axon growth; and inhibiting remyelination of regenerated axons. TGF-β has been applied to the treatment of peripheral nerve injury in animal models. In this context, we review the functions of TGF-β in peripheral nerve regeneration and potential clinical applications.

A study on the therapeutic potential of graphene titanate nanocomposite for treating chemically induced arthritis in rats

Nanotechnology holds substantial promise in the innovative therapies for rheumatoid arthritis (RA). The current study was designed to synthesize and characterize a new graphene titanate nanocomposite (GTNc) and explore its anti-arthritic, anti-inflammatory, and antioxidant potencies against Complete Freund's adjuvant (CFA)-induced arthritis in rats, as well as investigate the underlying molecular mechanisms. Our characterization methods included XRD, FT-IR, SEM, EDX, zeta potential, practical size, and XRF to characterize the novel GTNc. Our findings revealed that arthritic rats treated with GTNc exhibited lower levels of RF, CRP, IL-1β, TNF-α, IL-17, and ADAMTS-5, and higher levels of IL-4 and TIMP-3. In arthritic rats, GTNc reduced LPO levels while increasing GSH content and GST antioxidant activity. Additionally, GTNc decreased the expression of the TGF-β mRNA gene in arthritic rats. Histopathological investigation showed that GTNc reduced inflammatory cell infiltration, cartilage degradation, and bone destruction in joint injuries caused by CFA in the arthritic rats. Collectively, the anti-arthritic, anti-inflammatory, and antioxidant properties of GTNc appear promising for future arthritis treatments and bone disability research.

Role of increased plasminogen activator inhibitor-1 and vitronectin in gestational diabetes mellitus

OBJECTIVE

The aim of this study was to analyze the second-trimester levels of vitronectin and plasminogen activator inhibitor-1 in gestational diabetes mellitus.

METHODS

This study was conducted between September 2020 and December 2020 at the University of Health Sciences, Bursa Yuksek Ihtisas Research and Training Hospital, Department of Obstetrics and Gynecology. A total of 30 pregnant women with gestational diabetes mellitus and 60 healthy controls between 24 and 27/6 weeks of gestation were included. The inclusion criteria were as follows: being between 18 and 45 years old and 24-27/6 gestational weeks, having singleton pregnancy, diagnosed with gestational diabetes mellitus by using a two-step challenge test. The exclusion criteria of this study were as follows: chronic inflammatory or infectious disease, fasting blood glucose>126 mg/dL, intolerance to glucose tolerance testing, abnormal liver or kidney function tests, as well as pregnancy with pre-gestational diabetes history of adverse perinatal outcomes. Serum vitronectin and plasminogen activator inhibitor-1 levels were measured using the enzyme-linked immunosorbent assay method.

RESULTS

Vitronectin and plasminogen activator inhibitor-1 levels were higher in the gestational diabetes mellitus group compared with controls [91.85 (23.08) vs. 80.10 (39.18) ng/mL, for vitronectin and 6.50 (1.05) vs. 4.35(1.0) ng/mL, for plasminogen activator inhibitor-1 (for both p<0.001)]. vitronectin >84.7 ng/mL was found to predict gestational diabetes mellitus with a sensitivity of 70% and specificity of 63.3%. Moreover, vitronectin had a significant positive correlation with fasting blood glucose (r=0.476, p<0.001), postprandial blood glucose (r=0.489, p<0.001), HbA1c (r=0.713, p<0.001), and plasminogen activator inhibitor-1 (r=0.586, p<0.001).

CONCLUSION

This study revealed that second-trimester vitronectin and plasminogen activator inhibitor-1 are increased in gestational diabetes mellitus and vitronectin could be a candidate for the prediction of gestational diabetes mellitus.

Vitronectin Destroyed Intestinal Epithelial Cell Differentiation through Activation of PDE4-Mediated Ferroptosis in Inflammatory Bowel Disease

Objective

Vitronectin (VTN) has been reported to trigger cell pyroptosis to aggravate inflammation in our previous study. However, the function of VTN in inflammatory bowel disease (IBD) remains to be addressed.

Methods

Real-time PCR and western blotting were performed to analyze VTN-regulated intestinal epithelial cell (IEC) differentiation through ferroptosis, and immunofluorescence (IF), luciferase, and chromatin immunoprecipitation were used to identify whether VTN-modulated ferroptosis is dependent on phosphodiesterase 4 (PDE4)/protein kinase A (PKA)/cyclic adenosine monophosphate-response element-binding protein (CREB) cascade pathway. In vivo experiment in mice and a pilot study in patients with IBD were used to confirm inhibition of PDE4-alleviated IECs ferroptosis, leading to cell differentiation during mucosal healing.

Results

Herein, we found that caudal-related homeobox transcription factor 2-mediated IECs differentiation was impaired in response to VTN, which was attributed to enhanced ferroptosis characterized by decreased glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 expression. Inhibition of ferroptosis in IECs rescued the inhibitory effect of VTN on cell differentiation. Further analysis showed that VTN triggered phosphorylation of PDE4, leading to inhibit PKA/CREB activation and CREB nuclear translocation, which further reduced GPX4 transactivation. Endogenous PKA interacted with CREB, and this interaction was destroyed in response to VTN stimulation. What is more, overexpression of CREB in CaCO₂ cells overcame the promotion of VTN on ferroptosis. Most importantly, inhibition of PDE4 by roflumilast or dipyridamole could alleviate dextran sulfate sodium-induced colitis in mice and in a pilot clinical study confirmed by IF.

Conclusions

These findings demonstrated that highly expressed VTN disrupted IECs differentiation through PDE4-mediated ferroptosis in IBD, suggesting targeting PDE4 could be a promising therapeutic strategy for patients with IBD.

Expression and diagnostic significance of integrin beta-2 in synovial fluid of patients with osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is characterized by synovial cartilage degeneration and is the leading cause of disability and pain worldwide. This study sought to investigate the expression of integrin beta-2 (ITGB2) in synovial fluid of OA patients and its clinical significance.

METHODS

A total of 110 OA patients were enrolled, who were classified into grade I (N = 35), II (N = 42), and III (N = 33) according to the Kellgren-Lawrence classification, with 110 healthy subjects as controls, and their clinical data were compared. ITGB2 level was detected by RT-qPCR. The receiver operating characteristic curve was used to analyze the predictive value of ITGB2 on OA occurrence. The correlation between ITGB2 and bone metabolism indexes procollagen type I N-terminal peptide (PINP), bone glaprotein (BGP), bone alkaline phosphatase (BALP), and β-collagen I telopeptide (β-CTX) was analyzed by the Pearson method. Logistic regression model was performed to analyze the influencing factors of OA.

RESULTS

The content of red blood cells, white blood cells, PINP, BGP, and BALP was lowered in OA patients, while β-CTX was elevated. ITGB2 was highly-expressed in OA patients, negatively-correlated with PINP, BGP, and BALP, but positively-correlated with β-CTX. ITGB2 level increased with the elevation of OA grade. The ITGB2 level >1.375 had certain diagnostic values for OA. ITGB2 level is related to OA severity and may be a biomarker for OA classification. ITGB2 was an independent risk factor for OA.

CONCLUSION

High expression of ITGB2 in synovial fluid can assist OA diagnosis and may be a biomarker for OA grade.

A Novel Hydroxyapatite/Vitamin B12 Nanoformula for Treatment of Bone Damage: Preparation, Characterization, and Anti-Arthritic, Anti-Inflammatory, and Antioxidant Activities in Chemically Induced Arthritic Rats

The usage of nanomaterials for rheumatoid arthritis (RA) treatment can improve bioavailability and enable selective targeting. The current study prepares and evaluates the in vivo biological effects of a novel hydroxyapatite/vitamin B₁₂ nanoformula in Complete Freund's adjuvant-induced arthritis in rats. The synthesized nanoformula was characterized using XRD, FTIR, BET analysis, HERTEM, SEM, particle size, and zeta potential. We synthesized pure HAP NPs with 71.01% loading weight percentages of Vit B12 and 49 mg/g loading capacity. Loading of vitamin B₁₂ on hydroxyapatite was modeled by Monte Carlo simulation. Anti-arthritic, anti-inflammatory, and antioxidant effects of the prepared nanoformula were assessed. Treated arthritic rats showed lower levels of RF and CRP, IL-1β, TNF-α, IL-17, and ADAMTS-5, but higher IL-4 and TIMP-3 levels. In addition, the prepared nanoformula increased GSH content and GST antioxidant activity while decreasing LPO levels. Furthermore, it reduced the expression of TGF-β mRNA. Histopathological examinations revealed an improvement in joint injuries through the reduction of inflammatory cell infiltration, cartilage deterioration, and bone damage caused by Complete Freund's adjuvant. These findings indicate that the anti-arthritic, antioxidant, and anti-inflammatory properties of the prepared nanoformula could be useful for the development of new anti-arthritic treatments.

Knockdown of FBLN2 suppresses TGF-β1-induced MRC-5 cell migration and fibrosis by downregulating VTN

Idiopathic pulmonary fibrosis (IPF) is a common chronic and progressive lung disease. Fibulin-2 (FBLN2) is upregulated in patients with IPF; however, its exact role in IPF remains unclear. The present study aimed to investigate the role and the regulatory mechanism of FBLN2 in TGF-β1-induced fibrogenesis using human lung fibroblast-derived MRC-5 cells. Cell transfection was performed to regulate FBLN2 expression. Reverse transcription-quantitative PCR and western blot analyses were performed to detect the expression levels of FBLN2 and vitronectin (VTN). Cell viability and migration were determined via the Cell Counting Kit-8 and wound healing assays, respectively. Immunofluorescence was performed to detect α-smooth muscle actin (α-SMA)-positive cells. The STRING database was used to predict the interaction between FBLN2 and VTN, which was verified via the protein immunoprecipitation assay. The results demonstrated that inhibition of FBLN2 notably inhibited TGF-β1-induced proliferation and migration, as well as downregulating the protein expression levels of MMP2 and MMP9 in MRC-5 cells. In addition, inhibition of FBLN2 suppressed the expression levels of α-SMA, collagen type 1 α1 and fibronectin. FBLN2 was demonstrated to bind to VTN and negatively regulate its expression. Furthermore, overexpression of VTN partly abolished the inhibitory effects of FBLN2 knockdown on TGF-β1-induced proliferation, migration and fibrosis, as well as the activity of focal adhesion kinase (FAK) signaling. Taken together, the results of the present study suggest that FBLN2 knockdown can attenuate TGF-β1-induced fibrosis in MRC-5 cells by downregulating VTN expression via FAK signaling. Thus, FBLN2 may be a potential therapeutic target for IPF treatment.

Therapeutic Potential of Zeolites/Vitamin B12 Nanocomposite on Complete Freund's Adjuvant-Induced Arthritis as a Bone Disorder: In Vivo Study and Bio-Molecular Investigations

Rheumatoid arthritis (RA) is a long-term autoimmune disease. As nanotechnology has advanced, a growing number of nanodrugs have been used in the treatment of RA due to their unique physical and chemical properties. The purpose of this study was to assess the therapeutic potential of a novel zeolite/vitamin B12 nanocomposite (Nano ZT/Vit B12) formulation in complete Freund's adjuvant (CFA)-induced arthritis. The newly synthesized Nano ZT/Vit B12 was fully characterized using various techniques such as XRD, FT-IR, BET analysis, HERTEM, SEM, practical size, zeta potential, XRF, and EDX. The anti-arthritic, anti-inflammatory, and antioxidant activities as well as the immunomodulation effect of Nano ZT/Vit B12 on the CFA rat model of arthritis were examined. Histopathologic ankle joint injuries caused by CFA intrapedal injection included synovium hyperplasia, inflammatory cell infiltration, and extensive cartilage deterioration. The arthritic rats' Nano ZT/Vit B12 supplementation significantly improved these effects. Furthermore, in arthritic rats, Nano ZT/Vit B12 significantly reduced serum levels of RF and CRP, as well as the levels of IL-1β, TNF-α, IL-17, and ADAMTS-5, while increasing IL-4 and TIMP-3 levels. Nano-ZT/Vit B12 significantly declined the LPO level and increased antioxidant activities, such as GSH content and GST activity, in the arthritic rats. In arthritic rats, Nano ZT/Vit B12 also reduced TGF-β mRNA gene expression and MMP-13 protein levels. Collectively, Nano ZT/Vit B12 seems to have anti-arthritic, anti-inflammatory, and antioxidant properties, making it a promising option for RA in the future.

Osteoarthritis: pathogenic signaling pathways and therapeutic targets

Osteoarthritis (OA) is a chronic degenerative joint disorder that leads to disability and affects more than 500 million population worldwide. OA was believed to be caused by the wearing and tearing of articular cartilage, but it is now more commonly referred to as a chronic whole-joint disorder that is initiated with biochemical and cellular alterations in the synovial joint tissues, which leads to the histological and structural changes of the joint and ends up with the whole tissue dysfunction. Currently, there is no cure for OA, partly due to a lack of comprehensive understanding of the pathological mechanism of the initiation and progression of the disease. Therefore, a better understanding of pathological signaling pathways and key molecules involved in OA pathogenesis is crucial for therapeutic target design and drug development. In this review, we first summarize the epidemiology of OA, including its prevalence, incidence and burdens, and OA risk factors. We then focus on the roles and regulation of the pathological signaling pathways, such as Wnt/β-catenin, NF-κB, focal adhesion, HIFs, TGFβ/ΒΜP and FGF signaling pathways, and key regulators AMPK, mTOR, and RUNX2 in the onset and development of OA. In addition, the roles of factors associated with OA, including MMPs, ADAMTS/ADAMs, and PRG4, are discussed in detail. Finally, we provide updates on the current clinical therapies and clinical trials of biological treatments and drugs for OA. Research advances in basic knowledge of articular cartilage biology and OA pathogenesis will have a significant impact and translational value in developing OA therapeutic strategies.

Chrysin ameliorates synovitis and fibrosis of osteoarthritic fibroblast-like synoviocytes in rats through PERK/TXNIP/NLRP3 signaling

Objective: Synovitis and fibrosis are common pathological features of knee osteoarthritis (KOA). The interaction of synovitis and fibrosis can promote KOA progression. Chrysin (CHR), a natural flavonoid, may treat inflammation and prevent fibrosis. However, the effect and mechanism of CHR in KOA synovitis and fibrosis remains unclear. Methods: The KOA model was established in male SD rats by anterior cruciate ligament transection (ACLT), and histological analysis was used to evaluate synovitis and fibrosis. IL-6, IL-1β and TNF-α mRNA expression in synovial tissue was measured by qRT‒PCR. Immunohistochemistry (IHC) was performed to detect GRP78, ATF-6 and TXNIP expression in vivo. Synovial fibroblasts (SFs) were treated with TGF-β1 to stimulate the inflammatory response and fibrosis. CCK-8 assays were used to detect the viability of CHR-treated SFs. The IL-1β level was detected by immunofluorescence analysis. Coimmunoprecipitation (Co-IP) and double immunofluorescence colocalization were used to detect the physiological interaction between TXNIP and NLRP3. The expression of fibrosis-related mediators and PERK/TXNIP/NLRP3 signaling molecules was detected by western blotting and qRT-PCR. Results: Four weeks after CHR treatment, pathological sections and associated scores showed that CHR improved synovitis and fibrosis in the ACLT model. In vitro, CHR attenuated the TGF-β1-induced inflammatory response and fibrosis in SFs. Moreover, CHR suppressed the expression of synovial fibrosis markers and PERK/TXNIP/NLRP3 signaling molecules in the synovial tissue of rats with ACLT and cultured SFs. More importantly, we found that CHR inhibited TXNIP-NLRP3 interactions in TGF-β-induced SFs. Conclusion: Our findings indicate that CHR can ameliorate synovitis and fibrosis in KOA. The underlying mechanism may be related to the PERK/TXNIP/NLRP3 signaling pathway.

Development of Nanomaterials to Target Articular Cartilage for Osteoarthritis Therapy

Osteoarthritis (OA) is an obstinate, degradative, and complicated disease that has drawn much attention worldwide. Characterized by its stubborn symptoms and various sequela, OA causes much financial burden on both patients and the health system. What’s more, conventional systematic therapy is not effective enough and causes multiple side effects. There’s much evidence that nanoparticles have unique properties such as high penetration, biostability, and large specific surface area. Thus, it is urgent to exploit novel medications for OA. Nanomaterials have been sufficiently studied, exploiting diverse nano-drug delivery systems (DDSs) and targeted nano therapeutical molecules. The nanomaterials are primarily intra-articular injected under the advantages of high topical concentration and low dosage. After administration, the DDS and targeted nano therapeutical molecules can specifically react with the components, including cartilage and synovium of a joint in OA, furthermore attenuate the chondrocyte apoptosis, matrix degradation, and macrophage recruitment. Thus, arthritis would be alleviated. The DDSs could load with conventional anti-inflammatory drugs, antibodies, RNA, and so on, targeting chondrocytes, synovium, or extracellular matrix (ECM) and releasing the molecules sequentially. The targeted nano therapeutical molecules could directly get to the targeted tissue, alleviating the inflammation and promoting tissue healing. This review will comprehensively collect and evaluate the targeted nanomaterials to articular cartilage in OA.

CEMIP (KIAA1199) regulates inflammation, hyperplasia and fibrosis in osteoarthritis synovial membrane

Osteoarthritis (OA) synovial membrane is mainly characterized by low-grade inflammation, hyperplasia with increased cell proliferation and fibrosis. We previously underscored a critical role for CEMIP in fibrosis of OA cartilage. However, its role in OA synovial membrane remains unknown. An in vitro model with fibroblast-like synoviocytes from OA patients and an in vivo model with collagenase-induced OA mice were used to evaluate CEMIP-silencing effects on inflammation, hyperplasia and fibrosis. Our results showed that i. CEMIP expression was increased in human and mouse inflamed synovial membrane; ii. CEMIP regulated the inflammatory response pathway and inflammatory cytokines production in vitro and in vivo; iii. CEMIP induced epithelial to mesenchymal transition pathway and fibrotic markers in vitro and in vivo; iv. CEMIP increased cell proliferation and synovial hyperplasia; v. CEMIP expression was increased by inflammatory cytokines and by TGF-β signaling; vi. anti-fibrotic drugs decreased CEMIP expression. All these findings highlighted the central role of CEMIP in OA synovial membrane development and underscored that targeting CEMIP could be a new therapeutic approach.

Antifibrotic effect of brown algae-derived fucoidans on osteoarthritic fibroblast-like synoviocytes

Synovial fibrosis is a pathological process which contributes to joint pain and stiffness in several musculoskeletal disorders. Fucoidans, sulfated polysaccharides found in brown algae, have recently emerged as promising therapeutic agents. Despite the increasing amount of evidence suggesting the protective role of fucoidans in different experimental approaches of human fibrotic disorders, the effect of these sulfated polysaccharides on synovial fibrosis has not been investigated yet. By an in vitro experimental approach in fibroblast-like synoviocytes, we detected that fucoidans inhibit their differentiation into myofibroblasts with tumor cell-like characteristics and restore apoptosis. Composition and structure of fucoidan appear to be critical for the detected activity. Furthermore, protective effects of these sulfated polysaccharides are mediated by upregulation of nitric oxide production and modulation of TGF-β/smad pathway. Altogether, our results support the use of fucoidans as therapeutic compounds in the treatment of the fibrotic processes involved in rheumatic pathologies.

Urinary exosomal vitronectin predicts vesicoureteral reflux in patients with neurogenic bladders and spinal cord injuries

Neurogenic bladder (NGB) is an important complication of urinary tract dysfunction after spinal cord injury (SCI). However, using urodynamics and urography to guide therapy remains invasive and complicated. Therefore, the present study aimed to identify potential noninvasive biomarkers from urinary exosomes that can facilitate diagnosis and guide prognosis of patients with NGB subsequent to SCI. Urinary exosomes were isolated, and their proteome profile was analyzed by mass spectrometry. Transmission electron microscopy and Nanoparticle Tracking Analysis confirmed the size and morphological characteristics of urinary exosomes. In addition, bioinformatics analysis and parallel reaction monitoring (PRM) were used to screen candidate biomarkers. The selected biomarkers were validated using western blotting and ELISA. Mass spectrometry identified 134 upregulated proteins and 99 downregulated proteins between the vesicoureteral reflux (VUR) and non-VUR groups. A total of 18 candidate proteins were selected for PRM validation, but only vitronectin (VTN) and α-1 type I collagen (COL1A1) demonstrated significant differences. In the validation experiments using western blotting and ELISA, VTN was exclusively highly expressed in VUR patients compared with non-VUR patients. However, the ELISA results of COL1A1 revealed no significant difference when a larger sample size was used. Furthermore, a receiver operating characteristic curve of ELISA-based VTN demonstrated an area under the curve of 0.795 and 80% sensitivity at a threshold set to give 82.9% specificity. Collectively, these results suggested that VTN in urinary exosomes may be used as a biomarker to predict the progression and guide the prognosis of NGB.

Mechanistic Insight Into the Roles of Integrins in Osteoarthritis

Osteoarthritis (OA), one of the most common degenerative diseases, is characterized by progressive degeneration of the articular cartilage and subchondral bone, as well as the synovium. Integrins, comprising a family of heterodimeric transmembrane proteins containing α subunit and β subunit, play essential roles in various physiological functions of cells, such as cell attachment, movement, growth, differentiation, and mechanical signal conduction. Previous studies have shown that integrin dysfunction is involved in OA pathogenesis. This review article focuses on the roles of integrins in OA, especially in OA cartilage, subchondral bone and the synovium. A clear understanding of these roles may influence the future development of treatments for OA.

Fibroblast-like synoviocytes: Role in synovial fibrosis associated with osteoarthritis

The synovial membrane undergoes a variety of structural changes throughout the pathogenesis of osteoarthritis (OA), including the development of fibrosis. Fibroblast-like synoviocytes (FLS) are a heterogenous cell population of the synovium that are suggested to drive the fibrotic response, but the exact mechanisms associated with their activation in OA remain unclear. Once activated, FLS are suggested to acquire a myofibroblast-like phenotype that drives fibrogenesis through excessive extracellular matrix (ECM) component deposition and an enhanced contractile function. In this review, we define FLS in the synovium, discuss how select extracellular or endogenous factors potentially induce their activation in OA, and describe how the activity of myofibroblast-like cells affects the structure of the synovial membrane.