CircRNA CDR1as affects functional repair after spinal cord injury and regulates fibrosis through the SMAD pathway.

Spinal cord injury (SCI) is a complex problem in modern medicine. Fibroblast activation and fibroscarring after SCI impede nerve recovery. Non-coding RNA plays an important role in the progression of many diseases, but the study of its role in the progression of spinal fibrosis is still emerging. Here, we investigated the function of circular RNAs, specifically antisense to the cerebellar degeneration-related protein 1 (CDR1as), in spinal fibrosis and characterized its molecular mechanism and pathophysiology. The presence of CDR1as in the spinal cord was verified by sequencing and RNA expression assays. The effects of inhibition of CDR1as on scar formation, inflammation and nerve regeneration after spinal cord injury were investigated in vivo and in vitro. Further, gene expression of miR-7a-5p and protein expression of transforming Growth Factor Beta Receptor II (TGF-ßR2) were measured to evaluate their predicted interactions with CDR1as. The regulatory effects and activation pathways were subsequently verified by miR-7a-5p inhibitor and siCDR1as. These results indicate that CDR1as/miR-7a-5p/TGF-ßR2 interactions may exert scars and nerves functions and suggest potential therapeutic targets for treating spinal fibrotic diseases.

Selective oral ROCK2 inhibitor down-regulates IL-21 and IL-17 secretion in human T cells via STAT3-dependent mechanism.

Rho-associated kinase 2 (ROCK2) regulates the secretion of proinflammatory cytokines and the development of autoimmunity in mice. Data from a phase 1 clinical trial demonstrate that oral administration of KD025, a selective ROCK2 inhibitor, to healthy human subjects down-regulates the ability of T cells to secrete IL-21 and IL-17 by 90% and 60%, respectively, but not IFN-γ in response to T-cell receptor stimulation in vitro. Pharmacological inhibition with KD025 or siRNA-mediated inhibition of ROCK2, but not ROCK1, significantly diminished STAT3 phosphorylation and binding to IL-17 and IL-21 promoters and reduced IFN regulatory factor 4 and nuclear hormone RAR-related orphan receptor γt protein levels in T cells derived from healthy subjects or rheumatoid arthritis patients. Simultaneously, treatment with KD025 also promotes the suppressive function of regulatory T cells through up-regulation of STAT5 phosphorylation and positive regulation of forkhead box p3 expression. The administration of KD025 in vivo down-regulates the progression of collagen-induced arthritis in mice via targeting of the Th17-mediated pathway. Thus, ROCK2 signaling appears to be instrumental in regulating the balance between proinflammatory and regulatory T-cell subsets. Targeting of ROCK2 in man may therefore restore disrupted immune homeostasis and have a role in the treatment of autoimmunity.

Progranulin protects against osteoarthritis through interacting with TNF-α and ß-Catenin signalling.

OBJECTIVE: Progranulin (PGRN) was previously isolated as an osteoarthritis (OA)-associated growth factor. Additionally, PGRN was found to play a therapeutic role in inflammatory arthritis mice models through antagonising tumour necrosis factor α (TNF-α). This study was aimed at investigating the role of PGRN in degradation of cartilage and progression of OA. METHODS: Progression of OA was analysed in both spontaneous and surgically induced OA models in wild type and PGRN-deficient mice. Cartilage degradation and OA were evaluated using Safranin O staining, immunohistochemistry and ELISA. Additionally, mRNA expression of degenerative factors and catabolic markers known to be involved in cartilage degeneration in OA were analysed. Furthermore, the anabolic effects and underlying mechanisms of PGRN were investigated by in vitro experiments with primary chondrocytes. RESULTS: Here, we found that deficiency of PGRN led to spontaneous OA-like phenotype in 'aged' mice. Additionally, PGRN-deficient mice exhibited exaggerated breakdown of cartilage structure and OA progression, while local delivery of recombinant PGRN protein attenuated degradation of cartilage matrix and protected against OA development in surgically induced OA models. Furthermore, PGRN activated extracellular signal-regulated kinases (ERK) 1/2 signalling and elevated the levels of anabolic biomarkers in human chondrocyte, and the protective function of PGRN was mediated mainly through TNF receptor 2. Additionally, PGRN suppressed inflammatory action of TNF-α and inhibited the activation of ß-Catenin signalling in cartilage and chondrocytes. CONCLUSIONS: Collectively, this study provides new insight into the pathogenesis of OA, and also presents PGRN as a potential target for the treatment of joint degenerative diseases, including OA.

ADAMTS-12: a multifaced metalloproteinase in arthritis and inflammation.

ADAMTS-12 is a member of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family of proteases, which were known to play important roles in various biological and pathological processes, such as development, angiogenesis, inflammation, cancer, arthritis, and atherosclerosis. In this review, we briefly summarize the structural organization of ADAMTS-12; concentrate on the emerging role of ADAMTS-12 in several pathophysiological conditions, including intervertebral disc degeneration, tumorigenesis and angioinhibitory effects, pediatric stroke, gonad differentiation, trophoblast invasion, and genetic linkage to schizophrenia and asthma, with special focus on its role in arthritis and inflammation; and end with the perspective research of ADAMTS-12 and its potential as a promising diagnostic and therapeutic target in various kinds of diseases and conditions.

Metformin regulates bone marrow stromal cells to accelerate bone healing in diabetic mice.

Diabetes mellitus is a group of chronic diseases characterized by high blood glucose levels. Diabetic patients have a higher risk of sustaining osteoporotic fractures than non-diabetic people. The fracture healing is usually impaired in diabetics, and our understanding of the detrimental effects of hyperglycemia on fracture healing is still inadequate. Metformin is the first-line medicine for type 2 diabetes (T2D). However, its effects on bone in T2D patients remain to be studied. To assess the impacts of metformin on fracture healing, we compared the healing process of closed-wound fixed fracture, non-fixed radial fracture, and femoral drill-hole injury models in the T2D mice with and without metformin treatment. Our results demonstrated that metformin rescued the delayed bone healing and remolding in the T2D mice in all injury models. In vitro analysis indicated that compromised proliferation, osteogenesis, chondrogenesis of the bone marrow stromal cells (BMSCs) derived from the T2D mice were rescued by metformin treatment when compared to WT controls. Furthermore, metformin could effectively rescue the impaired detrimental lineage commitment of BMSCs isolated from the T2D mice in vivo as assessed by subcutaneous ossicle formation of the BMSC implants in recipient T2D mice. Moreover, the Safranin O staining of cartilage formation in the endochondral ossification under hyperglycemic condition significantly increased at day 14 post-fracture in the T2D mice receiving metformin treatment. The chondrocyte transcript factors SOX9 and PGC1α, important to maintain chondrocyte homeostasis, were both significantly upregulated in callus tissue isolated at the fracture site of metformin-treated MKR mice on day 12 post-fracture. Metformin also rescued the chondrocyte disc formation of BMSCs isolated from the T2D mice. Taken together, our study demonstrated that metformin facilitated bone healing, more specifically bone formation and chondrogenesis in T2D mouse models.

Digoxin protects against intervertebral disc degeneration via TNF/NF-κB and LRP4 signaling.

Background: Intervertebral disc degeneration (IVDD) is a leading cause of low back pain (LBP). The pathological process of IVDD is associated with inflammatory reactions and extracellular matrix (ECM) disorders. Digoxin is widely used for treating heart failure, and it has been reported to have anti-inflammatory effects. Objective: This study is to investigate the role of digoxin in the pathogenesis of intervertebral disc degeneration as well as the involved molecular mechanism, particularly the potential target protein. Methods: We exploited a rat needle model to investigate digoxin's role in intervertebral disc degeneration in vivo. Safranin O staining was used to measure cartilaginous tissue in the intervertebral disc. The morphological changes of intervertebral discs in animal models were determined by Hematoxylin-Eosin (H&E) staining and the pathological score. Primary nucleus pulposus cells (NP cells) from intervertebral discs of patients and murine were used in the present study. Western-Blotting assay, Real-time PCR assay, immunofluorescence staining, and immunochemistry were used to detect the role of digoxin in anti-TNF-α-induced inflammatory effects in vitro. Transfection of siRNA was used to regulate low-density lipoprotein receptor-related protein 4 (LRP4) expression in NP cells to investigate the potential protein target of digoxin. Results: Digoxin protected against intervertebral disc degeneration in rat needle models. Digoxin was found to exert its disc-protective effects through at least three different pathways by a) suppressing TNF-α-induced inflammation, b) attenuating ECM destruction, c) significantly promoting ECM anabolism. Additionally, LRP4 was found to be the downstream molecule of digoxin in NP cells for anti-inflammation and regulation of ECM metabolism. The knockdown of LRP4 downregulated the protective effect of digoxin in NP cells. Conclusion: These findings suggest that digoxin may be a potential therapeutic agent for intervertebral disc degeneration through anti-catabolism and pro-anabolism. Digoxin might also work as an alternative for other inflammation-related diseases.

Atsttrin regulates osteoblastogenesis and osteoclastogenesis through the TNFR pathway.

Osteoporosis is a systemic metabolic bone disorder for which inflammatory cytokines play an important role. To develop new osteoporosis treatments, strategies for improving the microenvironment for osteoblast and osteoclast balance are needed. Tumor necrosis factor-α (TNF-α) plays an important role in the initiation and development of osteoporosis. Atsttrin is an engineered protein derived from the growth factor, progranulin (PGRN). The present study investigates whether Atsttrin affects osteoclast formation and osteoblast formation. Here we show Atsttrin inhibits TNF-α-induced osteoclastogenesis and inflammation. Further mechanistic investigation indicates Atsttrin inhibits TNF-α-induced osteoclastogenesis through the TNFR1 signaling pathway. Moreover, Atsttrin rescues TNF-α-mediated inhibition of osteoblastogenesis via the TNFR1 pathway. Importantly, the present study indicates that while Atsttrin cannot directly induce osteoblastogenesis, it can significantly enhance osteoblastogenesis through TNFR2-Akt-Erk1/2 signaling. These results suggest that Atsttrin treatment could potentially be a strategy for maintaining proper bone homeostasis by regulating the osteoclast/osteoblast balance. Additionally, these results provide new insights for other bone metabolism-related diseases.

Gold nanocrystals: optical properties, fine-tuning of the shape, and biomedical applications.

Noble metal nanomaterials with special physical and chemical properties have attracted considerable attention in the past decades. In particular, Au nanocrystals (NCs), which possess high chemical inertness and unique surface plasmon resonance (SPR), have attracted extensive research interest. In this study, we review the properties and preparation of Au NCs with different morphologies as well as their important applications in biological detection. The preparation of Au NCs with different shapes by many methods such as seed-mediated growth method, seedless synthesis, polyol process, ultrasonic method, and hydrothermal treatment has already been introduced. In the seed-mediated growth method, the influence factors in determining the final shape of Au NCs are discussed. Au NCs, which show significant size-dependent color differences are proposed for preparing biological probes to detect biomacromolecules such as DNA and protein, while probe conjugate molecules serves as unique coupling agents with a target. Particularly, Au nanorods (NRs) have some unique advantages in the application of biological probes and photothermal cancer therapy compared to Au nanoparticles (NPs).

The Classification of Axial Deformity in Patients with Basilar Invagination.

OBJECTIVE: To summarize the variation types of the axis in patients with basilar invagination (BI), then propose a classification scheme of the axis deformity. METHODS: From December 2013 to September 2020, 92 patients (male 42, female 50) who were diagnosed with BI were studied retrospectively. Based on the imaging data of CT, the width and height of the axis pedicle and the sagittal diameter of the lateral mass were measured in each patient. According to the development of axis pedicle and lateral mass, the types of axis variation were summarized, and then the classification scheme of axis deformity was put forward. RESULTS: All cases were analyzed and axis deformities were divided into four types. Type I: the axis is basically normal (53 cases, 57.6%). Type II: axis lateral mass is dysplasia (eight cases, 8.7%), which includes two subtypes: type IIA, the axis unilateral lateral mass is dysplasia (three cases); type IIB, the axis bilateral lateral masses are all dysplasia (five cases). Type III: axis pedicle is dysplasia (11 cases, 12%), which is subdivided into two subtypes: type IIIA, the axis unilateral pedicle is dysplasia (six cases); type IIIB, the axis bilateral pedicles are all dysplasia (five cases). Type IV: axis pedicle and lateral mass are all dysplasia (20 cases, 21.7%), this type contains the following four subtypes: type IVA, the unilateral axis pedicle and unilateral lateral mass (contralateral or ipsilateral) are all hypoplasia (four cases); type IVB, the unilateral axis pedicle and bilateral lateral masses are all hypoplasia (five cases); type IVC, the bilateral axis pedicles and unilateral lateral mass are all dysplasia (seven cases); type IVD, the bilateral axis pedicles and bilateral lateral masses are all dysplasia (four cases). The left and right abnormal lateral mass sagittal diameter (Type II) was (7.23 ± 1.39) mm and (5.96 ± 1.37) mm, respectively, the left and right abnormal pedicle width (Type III) was (2.61 ± 1.01) mm and (3.23 ± 0.66) mm, respectively, left and right abnormal pedicle height (Type III) was (5.43 ± 2.19) mm and (4.92 ± 1.76) mm, respectively. Moreover, the classification scheme has good repeatability and credibility. CONCLUSIONS: The classification about axis deformity could provide personalized guidance for axis screw placement in the BI and other upper cervical surgery, and axis screw placement errors would be effectively avoided.

Follistatin-Like 1 Attenuation Suppresses Intervertebral Disc Degeneration in Mice through Interacting with TNF-α and Smad Signaling Pathway.

BACKGROUND: Inflammation plays an important role in intervertebral disc degeneration (IDD). The protein follistatin-like 1 (FSTL1) plays a proinflammatory role in a variety of inflammatory diseases. OBJECTIVES: The purpose of this study was to investigate whether IDD could be delayed by inhibiting FSTL-1 expression. METHODS: We established a puncture-induced IDD model in wild-type and FSTL-1+/- mice and collected intervertebral discs (IVDs) from the mice. Safranin O staining was used to detect cartilage loss of IVD tissue, and HE staining was used to detect morphological changes of IVD tissue. We measured the expression of FSTL-1 and related inflammatory indicators in IVD tissues by immunohistochemical staining, real-time PCR, and Western blotting. RESULTS: In the age-induced model of IDD, the level of FSTL-1 increased with the exacerbation of degeneration. In the puncture-induced IDD model, FSTL-1-knockdown mice showed a reduced degree of degeneration compared with that of wild-type mice. Further experiments showed that FSTL-1 knockdown also significantly reduced the level of related inflammatory factors in IVD. In vitro experiments showed that FSTL-1 knockdown significantly reduced TNF-α-induced inflammation. Specifically, the expression levels of the inflammatory factors COX-2, iNOS, MMP-13, and ADAMTS-5 were reduced. Knockdown of FSTL-1 attenuated inflammation by inhibiting the expression of P-Smad1/5/8, P-Erk1/2, and P-P65. CONCLUSION: Knockdown of FSTL-1 attenuated inflammation by inhibiting the TNF-α response and Smad pathway activity and ultimately delayed IDD.

Circular RNA Plek promotes fibrogenic activation by regulating the miR-135b-5p/TGF-ßR1 axis after spinal cord injury.

OBJECTIVES: The spinal cord rarely repairs itself when damaged; however, methods for encouraging nerves to regrow are on the horizon. Although circular RNAs (circRNAs) contribute to various biological processes, including neuronal processes, their functions in the subacute phase of spinal cord injury (SCI) have not been elucidated. In this study, we identified a novel circRNA, named CircPlek, with increased expression in spinal tissues after SCI. MATERIALS AND METHODS: We predicted a regulatory relationship between CircPlek and miR-135b-5p, which showed the most obvious decrease in post-SCI expression. We established the CircPlek/miR-135b-5p/transforming growth factor-beta receptor type I (TGF-ßR1) axis using a bioinformatics approach and further evaluated the potential function of the interaction network in vitro. RESULTS: We confirmed that in TGF-ß1-induced fibroblasts, the overexpression of miR-135b-5p or/and inhibition of CircPlek inhibited fibrosis activation via the Smad pathway. Inhibitors of miR-135b-5p had antagonistic effects on CircPlek. CONCLUSIONS: the CircPlek/miR-135b-5p/TGF-ßR1 axis may exert important functions in SCI and is a potential therapeutic target.

Progranulin promotes bone fracture healing via TNFR pathways in mice with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) significantly increases bone fragility and fracture risk. Progranulin (PGRN) promotes bone fracture healing in both physiological and type 1 diabetic conditions. The present study aimed to investigate the role of PGRN in T2DM bone fracture healing. MKR mice (with an FVB/N genetic background) were used as the T2DM model. Drill-hole and Bonnarens and Einhorn models were used to investigate the role of PGRN in T2DM fracture healing in vivo. Primary bone marrow cells were isolated for molecular and signaling studies, and reverse transcription-polymerase chain reaction, immunohistochemical staining, and western blotting were performed to assess PGRN effects in vitro. PGRN mRNA and protein expression were upregulated in the T2DM model. Local administration of recombinant PGRN effectively promoted T2DM bone fracture healing in vivo. Additionally, PGRN could induce anabolic metabolism during endochondral ossification through the TNFR2-Akt and Erk1/2 pathways. Furthermore, PGRN showed anti-inflammatory activity in the T2DM bone regeneration process. These findings suggest that local administration of exogenous PGRN may be an alternative strategy to support bone regeneration in patients with T2DM. Additionally, PGRN might hold therapeutic potential for other TNFR-related metabolic disorders.

Fexofenadine Protects Against Intervertebral Disc Degeneration Through TNF Signaling.

Objective: Fexofenadine (FFD) is an antihistamine drug with an anti-inflammatory effect. The intervertebral disc (IVD) degeneration process is involved in inflammation in which tumor necrosis factor-α (TNF-α) plays an important role. This study aims to investigate the role of FFD in the pathological process of IVD degeneration. Methods: Safranin O staining was used for the measurement of cartilageous tissue in the disc. Hematoxylin-Eosin (H&E) staining was used to determine the disc construction. A rat needle puncture model was taken advantage of to examine the role of FFD in disc degeneration in vivo. Western Blotting assay, immunochemistry, and immunoflurence staining were used for the determination of inflammatory molecules. ELISA assay was performed to detect the release of inflammatory cytokines. A real-time PCR assay was analyzed to determine the transcriptional expressions of molecules. Results: Elevated TNF-α resulted in inflammatory disc degeneration, while FFD protected against TNF-α-induced IVD degeneration. Mechanism study found FFD exhibited a disc protective effect through at least two pathways. (a) FFD inhibited TNF-α-mediated extracellular matrix (ECM) degradation and (b) FFD rescued TNF-α induced inflammation in disc degeneration. Furthermore, the present study found that FFD suppressed TNF-α mediated disc degeneration via the cPLA2/NF-κB signaling pathway. Conclusions: FFD provided another alternative for treating disc degeneration through a novel mechanism. Additionally, FFD may also be a potential target for the treatment of other inflammatory-related diseases, including IVD degeneration.

Atsttrin Promotes Cartilage Repair Primarily Through TNFR2-Akt Pathway.

BACKGROUND: Cartilage defects account for substantial economic and humanistic burdens and pose a significant clinical problem. The efficacy of clinical approaches to cartilage repair is often inadequate, in part, owing to the restricted proliferative capacity of chondrocytes. Molecules have the capacity to promote the differentiation of multipotent mesenchymal stem cells into chondrocytes and may also gain the ability to repair the damaged cartilage. OBJECTIVE: This study aimed to investigate the role of Atsttrin (progranulin-derived engineered protein) in cartilage repair as well as the signaling pathway involved. METHODS: Primary and mesenchymal stem cell lines were used for the micromass culture. A murine cartilage defect model was used to determine the role of Atsttrin in cartilage repair in vivo. Real-time polymerase chain reaction and Western blot analysis were used to monitor the effect of Atsttrin on the transcriptional and protein levels, respectively, of key anabolic and catabolic signaling molecules. RESULTS: Atsttrin stimulated chondrogenesis in vitro and accelerated cartilage repair in vivo. In addition, Atsttrin-mediated cartilage repair occurred primarily through tumor necrosis factor receptor 2-initiated Akt signaling and downstream JunB transcription factor. CONCLUSION: Atsttrin might serve as a promising therapeutic modality for cartilage regeneration.

Progranulin promotes diabetic fracture healing in mice with type 1 diabetes.

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by insulin deficiency, and patients with diabetes have an increased risk of bone fracture and significantly impaired fracture healing. Proinflammatory cytokine tumor necrosis factor-alpha is significantly upregulated in diabetic fractures and is believed to underlie delayed fracture healing commonly observed in diabetes. Our previous genetic screen for the binding partners of progranulin (PGRN), a growth factor-like molecule that induces chondrogenesis, led to the identification of tumor necrosis factor receptors (TNFRs) as the PGRN-binding receptors. In this study, we employed several in vivo models to ascertain whether PGRN has therapeutic effects in diabetic fracture healing. Here, we report that deletion of PGRN significantly delayed bone fracture healing and aggravated inflammation in the fracture models of mice with T1DM. In contrast, recombinant PGRN effectively promoted diabetic fracture healing by inhibiting inflammation and enhancing chondrogenesis. In addition, both TNFR1 proinflammatory and TNFR2 anti-inflammatory signaling pathways are involved in PGRN-stimulated diabetic fracture healing. Collectively, these findings illuminate a novel understanding concerning the role of PGRN in diabetic fracture healing and may have an application in the development of novel therapeutic intervention strategies for diabetic and other types of impaired fracture healing.

Dynamic Change of Lumbar Structure and Associated Factors: A Retrospective Study.

OBJECTIVE: To determine whether lumbar anatomy parameters are in dynamic change and related factors. METHODS: This is a retrospective study. Participants who did lumbar computed tomography (CT) scanning in Shandong University Qilu Hospital from October 2017 to March 2019 were selected. The 476 participants were randomly selected as male or female, with the age ranging from 17 to 87 years (mean, 55.19; standard deviation, 14.28 years). All the measurements were taken based on the CT scanning image and the measurement of lumbar morphology was conducted using picture archiving and communication systems (PACS). The angle between the horizontal alignment and pedicle center on median sagittal view, the angle between upper endplate and lower endplate on median sagittal view as well as transverse section angle (TSA) using Magerl point in the axial view was determined by reconstructive CT analysis. RESULTS: In the overall participants, the angle between the horizontal alignment and pedicle center on median sagittal view of lumbar one to three was significantly decreased with aging, from 3.90° ± 2.81° to -4.18° ± 6.86° (P = 0.002), 5.60° ± 2.89° to -4.14° ± 5.90° (P = 0.030), and 4.75° ± 2.95° to -2.87° ± 4.68° (P < 0.001), respectively. Additionally, the angle between the horizontal alignment and pedicle center on median sagittal view in male participants of lumbar two was dramatically decreased, from 4.83° ± 2.79° to -4.45° ± 5.97° (P = 0.30). And that of lumbar three in female participants was significantly decreased, from 4.56° ± 2.52° to -2.88° ± 5.03° (P = 0.029). Furthermore, of the overall participants, the angle between upper endplate and lower endplate on median sagittal view of lumbar one to four was associated with aging (P < 0.001, P < 0.001, P = 0.015, P < 0.001, respectively). The angle of lumbar one, two and four in male participants and lumbar one to four in female participants were all significantly related to aging (all P < 0.05). Moreover, in the participants overall, the TSA of lumbar one to three was significantly associated with aging (P = 0.015, P = 0.006 and P = 0.007, respectively). In addition, this angle in lumbar one to lumbar four in male participants were all negatively associated with aging (P = 0.017, P = 0.001, P = 0.005 and P = 0.036, respectively). CONCLUSION: Lumbar anatomy parameters are in dynamic change in an age and gender dependent manner. During spine surgery in elderly patients, more attention should be paid to these anatomic changes.

Establishment of a Modified Collagen-Induced Arthritis Mouse Model to Investigate the Anti-inflammatory Activity of Progranulin in Inflammatory Arthritis.

Progranulin (PGRN) was found to play an anti-inflammatory and protective role in both inflammatory and degenerative arthritis (Tang et al., Science 332:478-484, 2011; Zhao et al., Ann Rheum Dis 74:2244-2253, 2015). We recently published a visualized protocol to demonstrate a surgically-induced mouse model for examining the protective role of PGRN in degenerative osteoarthritis (Zhao et al., J Vis Exp:e50924, 2014). Herein we describe a modified collagen-induced arthritis (CIA) mouse model to investigate the anti-inflammatory activity of PGRN in inflammatory arthritis. CIA model is the most commonly used autoimmune model of inflammatory arthritis which shares both immunological and pathological features with human rheumatoid arthritis. Autoimmune inflammatory arthritis is induced by immunization with an emulsion of complete Freund's adjuvant and chicken type II collagen (CII) using a modified procedure in PGRN deficient mice and control littermates. Using the protocol described here, the investigator should be able to reproducibly induce a high incidence of CIA in PGRN deficient mice and also learn how to critically evaluate the severity and incidence of this disease model.

Progranulin Is Positively Associated with Intervertebral Disc Degeneration by Interaction with IL-10 and IL-17 Through TNF Pathways.

Progranulin (PGRN) is a widely expressed growth factor that effectively inhibits tumor necrosis factor α (TNFα)-mediated inflammatory response. TNFα is involved in intervertebral disc degeneration (IDD) and plays a key role. This study aims to determine the role of PGRN in the intervertebral disc degeneration process. We collected intervertebral discs (IVDs) from humans and mice with different genetic backgrounds. We examined the expression of PGRN in IVD tissues by immunohistochemistry staining and Western blotting assay. We examined the peripheral serum level of PGRN by ELISA assay. Murine IVD tissue samples were taken to undergo safranin O, HE, and immunohistochemistry staining. Primary human nucleus pulposus cells were used for ELISA and RT-PCR assays. PGRN as well as interlukin-10 (IL-10) and interlukin-17 (IL-17) expressions were elevated in degenerative discs and peripheral blood sera. Loss of PGRN led to accelerated disc degeneration in the animal model, along with decreased expression of IL-10 and increased expression of IL-17. Additionally, the PGRN level was positively related to levels of IL-10 and IL-17. In vitro study suggested that PGRN protected against disc degeneration by inducing IL-10 and reducing IL-17. PGRN is associated with intervertebral disc degeneration through interfering with IL-10 and IL-17; thus, PGRN could be an interesting biomarker for diagnosis and a potential treatment target.

Role of ADAMTS-12 in Protecting Against Inflammatory Arthritis in Mice By Interacting With and Inactivating Proinflammatory Connective Tissue Growth Factor.

OBJECTIVE: It has been reported that ADAMTS-12 is a susceptibility gene for rheumatoid arthritis (RA) development, and its level is significantly increased in RA patients. In addition, ADAMTS-12 is reported to be required for inflammation in otherwise healthy subjects. This study was undertaken to determine the role of ADAMTS-12 and the underlying mechanisms in the pathogenesis of inflammatory arthritis. METHODS: The collagen-induced arthritis (CIA) model was established in ADAMTS-12-deficient mice and their control littermates to determine the role of ADAMTS-12 in vivo. Micro-computed tomography scanning was used to demonstrate the destruction of the ankle joint; histologic analysis illustrated synovitis, pannus formation, and bone and cartilage destruction; enzyme-linked immunosorbent assay was performed to measure serum levels of inflammatory cytokines; and protein-protein interaction assays were performed to detect the interactions of ADAMTS-12 and its various deletion mutants with connective tissue growth factor (CTGF). RESULTS: Deficiency of ADAMTS-12 led to accelerated inflammatory arthritis in the CIA mouse model. Loss of ADAMTS-12 caused enhanced osteoclastogenesis. In vitro and in vivo protein-protein interaction assays demonstrated that ADAMTS-12 bound and processed CTGF, a previously unrecognized substrate of ADAMTS-12. In addition, deletion of ADAMTS-12 enhanced, while overexpression of ADMATS-12 reduced, CTGF-mediated inflammation. Furthermore, ADAMTS-12 regulation of inflammation was largely lost in CTGF-deficient macrophages. Importantly, blocking of CTGF attenuated elevated inflammatory arthritis seen in the ADAMTS-12-deficient CIA mouse model. CONCLUSION: This study provides evidence that ADAMTS-12 is a critical regulator of inflammatory arthritis and that this is mediated, at least in part, through control of CTGF turnover.

Progranulin derived engineered protein Atsttrin suppresses TNF-α-mediated inflammation in intervertebral disc degenerative disease.

Atsttrin, an engineered molecule composed of three fragments of progranulin(PGRN), exerts comparable anti-inflammation ability. Intervertebral disc degeneration (IDD) is involved in inflammation in which TNF-α plays a key role. This study aims to examine the effect and the mechanism of Atsttrin in the pathogenesis of intervertebral disc degeneration. For this purpose, we took advantage of murine and human intervertebral disc (IVD) and examined the expression of TNF-α in IVD tissues using immunohistochemistry and TNF-α level in peripheral sera by ELISA assay. Moreover, murine IVD was taken to undergo the Safranin O and HE staining. Furthermore, primary human nucleus pulposus cells were used for immunohistochemistry staining, fluorescent staining, Western Blot, ELISA assay and RT-PCR assay. Herein we found TNF-α expression was elevated in intervertebral disc and peripheral sera in patients with IDD. Interestingly, Atsttrin effectively inhibited TNF-α-mediated catabolism in murine disc by ex vivo study. TNF-α-induced inflammatory cytokines were strongly reduced in presence of Atsttrin in primary human disc. Mechanism study indicated Atsttrin protected against intervertebral disc degeneration by inhibiting TNF-α-induced inflammation. These findings show that Atsttrin is a potential molecular target for disc degenerative diseases.