Clinical Significance of Plasma Tenascin-C Levels in Recipients With Prolonged Jaundice After Living Donor Liver Transplantation.

BACKGROUND: Focusing on tenascin-C (TNC), whose expression is enhanced during the tissue remodeling process, the present study aimed to clarify whether plasma TNC levels after living donor liver transplantation (LDLT) could be a predictor of irreversible liver damage in the recipients with prolonged jaundice (PJ). METHODS: Among 123 adult recipients who underwent LDLT between March 2002 and December 2016, the subjects were 79 recipients in whom we could measure plasma TNC levels preoperatively (pre-) and on postoperative days 1 to 14 (POD1 to POD14). Prolonged jaundice was defined as serum total bilirubin level >10 mg/dL on POD14, and 79 recipients were divided into 2 groups: 56 in the non-PJ (NJ) group and 23 in the PJ group. RESULTS: The PJ group had significantly increased pre-TNC; smaller grafts; decreased platelet counts POD14; increased TB-POD1, -POD7, and -POD14; increased prothrombin time-international normalized ratio on POD7 and POD14; and higher 90-day mortality than the NJ group. As for the risk factors for 90-day mortality, multivariate analysis identified TNC-POD14 as a single significant independent prognostic factor (P = .015). The best cut-off value of TNC-POD14 for 90-day survival was determined to be 193.7 ng/mL. In the PJ group, the patients with low TNC-POD14 (<193.7 ng/mL) had satisfactory survival, with 100.0 % at 90 days, while the patients with high TNC-POD14 (≥193.7 ng/mL) had significantly poor survival, with 38.5 % at 90 days (P = .004). CONCLUSIONS: In PJ after LDLT, plasma TNC-POD14 is very useful for diagnosing postoperative irreversible liver damage early.

Inhibition of AMPA (α-Amino-3-Hydroxy-5-Methyl-4-Isoxazole Propionate) Receptor Reduces Acute Blood-Brain Barrier Disruption After Subarachnoid Hemorrhage in Mice.

Activation of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) is thought to cause acute brain injury, but the role remains poorly understood in subarachnoid hemorrhage (SAH). This study was conducted to evaluate if AMPAR activation induces acute blood-brain barrier (BBB) disruption after SAH. C57BL/6 male adult mice (n = 117) underwent sham or filament perforation SAH modeling, followed by a random intraperitoneal injection of vehicle or two dosages (1 mg/kg or 3 mg/kg) of a selective noncompetitive AMPAR antagonist perampanel (PER) at 30 min post-modeling. The effects were evaluated by mortality, neurological scores, and brain water content at 24-48 h and video electroencephalogram monitoring, immunostaining, and Western blotting at 24 h post-SAH. PER significantly suppressed post-SAH neurological impairments, brain edema, and BBB disruption. SAH developed epileptiform spikes without obvious convulsion, which were also inhibited by PER. Western blotting showed that the expression of AMPAR subunits GluA1 and GluA2 was unchanged after SAH, but they were significantly activated after SAH. PER prevented post-SAH activation of GluA1/2, associated with the suppression of post-SAH induction of tenascin-C, a causative mediator of post-SAH BBB disruption. Meanwhile, an intracerebroventricular injection of a subtype-selective GluA1/2 agonist augmented the activation of GluA1/2 and the induction of tenascin-C in brain capillary endothelial cells and aggravated post-SAH BBB disruption without increases in epileptiform spikes. Neurological impairments and brain edema were not correlated with the occurrence of epileptiform spikes. This study first showed that AMPAR plays an important role in the development of post-SAH BBB disruption and can be a novel therapeutic target against it.

Generation of Transgenic Mice that Conditionally Overexpress Tenascin-C.

Tenascin-C (TNC) is an extracellular matrix glycoprotein that is expressed during embryogenesis. It is not expressed in normal adults, but is up-regulated under pathological conditions. Although TNC knockout mice do not show a distinct phenotype, analyses of disease models using TNC knockout mice combined with in vitro experiments revealed the diverse functions of TNC. Since high TNC levels often predict a poor prognosis in various clinical settings, we developed a transgenic mouse that overexpresses TNC through Cre recombinase-mediated activation. Genomic walking showed that the transgene was integrated into and truncated the Atp8a2 gene. While homozygous transgenic mice showed a severe neurological phenotype, heterozygous mice were viable, fertile, and did not exhibit any distinct abnormalities. Breeding hemizygous mice with Nkx2.5 promoter-Cre or α-myosin heavy chain promoter Cre mice induced the heart-specific overexpression of TNC in embryos and adults. TNC-overexpressing mouse hearts did not have distinct histological or functional abnormalities. However, the expression of proinflammatory cytokines/chemokines was significantly up-regulated and mortality rates during the acute stage after myocardial infarction were significantly higher than those of the controls. Our novel transgenic mouse may be applied to investigations on the role of TNC overexpression in vivo in various tissue/organ pathologies using different Cre donors.

TNIIIA2, The Peptide of Tenascin-C, as a Candidate for Preventing Articular Cartilage Degeneration.

OBJECTIVE: TNIIIA2 is a peptide of the extracellular matrix glycoprotein tenascin-C. We evaluated whether intra-articular injection of TNIIIA2 could prevent articular cartilage degeneration without inducing synovitis in an osteoarthritis mice model. DESIGN: Ten micrograms per milliliter of TNIIIA2 were injected into the knee joint of mice (group II) to evaluate the induction of synovitis. The control group received an injection of phosphate buffered saline (group I). Synovitis was evaluated using synovitis score 2 and 4 weeks after injection. The ligaments of knee joints of mice were transected to make the osteoarthritis model. After transection, 10 µg/mL of TNIIIA2 was injected into the knee joint (group IV). The control group received an injection of phosphate buffered saline after transection (group III). Histologic examinations were made using hematoxylin and eosin and safranin-O staining at 2, 4, 8, and 12 weeks postoperatively. An in vitro study was also performed to determine the mechanism by which TNIIIA2 prevents cartilage degeneration. Human chondrocytes were isolated, cultured, and treated with TNIIIA2. The expressions of various mRNAs, including inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared using real-time polymerase chain reaction. RESULTS: There were no differences between groups in the study of intra-articular injection of mice (group I vs. group II). In the osteoarthritis model, we found development of osteoarthritis was suppressed in group IV at 4 and 8 weeks. TNIIIA2 upregulated the expressions of tumor necrosis factor-α, matrix metalloproteinase 3, and basic fibroblast growth factor. CONCLUSION: We demonstrated that TNIIIA2 could prevent cartilage degeneration without synovitis.

Tenascin-C in Osteoarthritis and Rheumatoid Arthritis.

Tenascin-C (TNC) is a large multimodular glycoprotein of the extracellular matrix that consists of four distinct domains. Emerging evidence suggests that TNC may be involved in the pathogenesis of osteoarthritis (OA) and rheumatoid arthritis (RA). In this review, we summarize the current understanding of the role of TNC in cartilage and in synovial biology, across both OA and RA. TNC is expressed in association with the development of articular cartilage; the expression decreases during maturation of chondrocytes and disappears almost completely in adult articular cartilage. TNC expression is increased in diseased cartilage, synovium, and synovial fluid in OA and RA. In addition, elevated circulating TNC levels have been detected in the blood of RA patients. Thus, TNC could be used as a novel biochemical marker for OA and RA, although it has no specificity as a biochemical marker for these joint disorders. In a post-traumatic OA model of aged joints, TNC deficiency was shown to enhance cartilage degeneration. Treatment with TNC domains results in different, domain-specific effects, which are also dose-dependent. For instance, some TNC fragments including the fibrinogen-like globe domain might function as endogenous inducers of synovitis and cartilage matrix degradation through binding with toll-like receptor-4, while full-length TNC promotes cartilage repair and prevents the development of OA without exacerbating synovitis. The TNC peptide TNIIIA2 also prevents cartilage degeneration without causing synovial inflammation. The clinical significance of TNC effects on cartilage and synovium is unclear and understanding the clinical significance of TNC is not straightforward.

Tenascin-C in cardiac disease: a sophisticated controller of inflammation, repair, and fibrosis.

Tenascin-C (TNC) is a large extracellular matrix glycoprotein classified as a matricellular protein that is generally upregulated at high levels during physiological and pathological tissue remodeling and is involved in important biological signaling pathways. In the heart, TNC is transiently expressed at several important steps during embryonic development and is sparsely detected in normal adult heart but is re-expressed in a spatiotemporally restricted manner under pathological conditions associated with inflammation, such as myocardial infarction, hypertensive cardiac fibrosis, myocarditis, dilated cardiomyopathy, and Kawasaki disease. Despite its characteristic and spatiotemporally restricted expression, TNC knockout mice develop a grossly normal phenotype. However, various disease models using TNC null mice combined with in vitro experiments have revealed many important functions for TNC and multiple molecular cascades that control cellular responses in inflammation, tissue repair, and even myocardial regeneration. TNC has context-dependent diverse functions and, thus, may exert both harmful and beneficial effects in damaged hearts. However, TNC appears to deteriorate adverse ventricular remodeling by proinflammatory and profibrotic effects in most cases. Its specific expression also makes TNC a feasible diagnostic biomarker and target for molecular imaging to assess inflammation in the heart. Several preclinical studies have shown the utility of TNC as a biomarker for assessing the prognosis of patients and selecting appropriate therapy, particularly for inflammatory heart diseases.

Tenascin-C Induces Phenotypic Changes in Fibroblasts to Myofibroblasts with High Contractility through the Integrin αvß1/Transforming Growth Factor ß/SMAD Signaling Axis in Human Breast Cancer.

Tenascin-C (TNC) is strongly expressed by fibroblasts and cancer cells in breast cancer. To assess the effects of TNC on stromal formation, we examined phenotypic changes in human mammary fibroblasts treated with TNC. The addition of TNC significantly up-regulated α-smooth muscle actin (α-SMA) and calponin. TNC increased the number of α-SMA- and/or calponin-positive cells with well-developed stress fibers in immunofluorescence, which enhanced contractile ability in collagen gel contraction. The treatment with TNC also significantly up-regulated its own synthesis. Double immunofluorescence of human breast cancer tissues showed α-SMA- and/or calponin-positive myofibroblasts in the TNC-deposited stroma. Among several receptors for TNC, the protein levels of the αv and ß1 integrin subunits were significantly increased after the treatment. Immunofluorescence showed the augmented colocalization of αv and ß1 at focal adhesions. Immunoprecipitation using an anti-αv antibody revealed a significant increase in coprecipitated ß1 with TNC in lysates. The knockdown of αv and ß1 suppressed the up-regulation of α-SMA and calponin. The addition of TNC induced the phosphorylation of SMAD2/3, whereas SB-505124 and SIS3 blocked myofibroblast differentiation. Therefore, TNC enhances its own synthesis by forming a positive feedback loop and increases integrin αvß1 heterodimer levels to activate transforming growth factor-ß signaling, which is followed by a change to highly contractile myofibroblasts. TNC may essentially contribute to the stiffer stromal formation characteristic of breast cancer tissues.

Intra-articular injection of rebamipide prevents articular cartilage degeneration in murine post-traumatic osteoarthritis models.

Objectives: Rebamipide is a protective drug used for gastric mucosal injuries, and it also exerts protective effects for a variety of other tissues. In this study, murine post-traumatic (PT) osteoarthritis (OA) models in vivo and human OA chondrocytes in vitro were used to examine the effects of rebamipide on articular cartilage degeneration.Methods: Male BALB/c mice were used. The knee ligaments were transected in both knees. Mice were injected with rebamipide into the knee joint every week. Human chondrocytes were stimulated with IL-1ß, then treated with or without rebamipide. The levels of mRNA expression of COL2A, IL-1ß, TNFα, NF-κB, MMP3, MMP13, ADAMTS5, TIMP3, FGF2, and TGFß were estimated using real-time PCR.Results: Histological scores were significantly better in the rebamipide 1 mg/mL and 10 mg/mL groups than in the control group. Rebamipide up-regulated the mRNA expressions of COL2A, TIMP3, TGFß, and FGF2 in chondrocytes and down-regulated IL-1ß, TNFα, NF-κB, MMP3, MMP13, and ADAMTS5.Conclusion: Intra-articular injection of rebamipide prevents articular cartilage degeneration for 6 weeks in murine models of OA in vivo. Rebamipide down-regulates inflammatory cytokines and catabolic factors and up-regulates anabolic factors in human chondrocytes in vitro. Rebamipide could be an important treatment for prevention of articular cartilage degeneration.

Toll-Like Receptor 4 and Tenascin-C Signaling in Cerebral Vasospasm and Brain Injuries After Subarachnoid Hemorrhage.

Toll-like receptor 4 (TLR4) is expressed in various cell types in the central nervous system and exerts maximal inflammatory responses among the TLR family members. TLR4 can be activated by many endogenous ligands having damage-associated molecular patterns including heme and fibrinogen at the rupture of a cerebral aneurysm, and therefore its activation is reasonable as an initial step of cascades to brain injuries after aneurysmal subarachnoid hemorrhage (SAH). TLR4 activation induces tenascin-C (TNC), a representative of matricellular proteins that are a class of inducible, nonstructural, secreted, and multifunctional extracellular matrix glycoproteins. TNC is also an endogenous activator and inducer of TLR4, forming positive feedback mechanisms leading to more activation of the signaling transduction. Our studies have demonstrated that TLR4 as well as TNC are involved in inflammatory reactions, blood-brain barrier disruption, neuronal apoptosis, and cerebral vasospasm after experimental SAH. This article reviews recent understanding of TLR4 and TNC in SAH to suggest that the TLR4-TNC signaling may be an important therapeutic target for post-SAH brain injuries.

Tenascin-C promotes the repair of cartilage defects in mice.

BACKGROUND: The effects of tenascin-C (TNC) on cartilage repair were examined in cartilage defect model mice. An in vitro study was also performed to determine the mechanism of cartilage repair with TNC. METHODS: Full-thickness osteochondral defects were filled with TNC (group A: 100 µg/ml, group B: 10 µg/ml, group C: empty). Mice were sacrificed at 1, 2, 3, and 6 weeks postoperatively. Cartilage repair was histologically evaluated using the modified WAKITANI score. Chondrocytes were isolated and cultured, and they were treated with TNC. The expressions of various mRNAs including TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared by real-time polymerase chain reaction. RESULTS: The defects in group A were covered with hyaline-like cartilage after 3 weeks. Average modified WAKITANI scores were significantly better in group A than in groups B and C at 3 and 6 weeks. TNC upregulated the expressions of endogenous TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage. TNC downregulated the expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5. CONCLUSIONS: Intra-articular injection of full-length TNC repaired cartilage in murine models of full-thickness osteochondral defects. TNC upregulated the expression of ADAMTS4, but downregulated the expression of ADAMTS5 that contributed to cartilage degradation.

Tenascin-C in brain injuries and edema after subarachnoid hemorrhage: Findings from basic and clinical studies.

Subarachnoid hemorrhage (SAH) by a rupture of cerebral aneurysms remains the most devastating cerebrovascular disease. Early brain injury (EBI) is increasingly recognized to be the primary determinant for poor outcomes, and also considered to cause delayed cerebral ischemia (DCI) after SAH. Both clinical and experimental literatures emphasize the impact of global cerebral edema in EBI as negative prognostic and direct pathological factors. The nature of the global cerebral edema is a mixture of cytotoxic and vasogenic edema, both of which may be caused by post-SAH induction of tenascin-C (TNC) that is an inducible, non-structural, secreted and multifunctional matricellular protein. Experimental SAH induces TNC in brain parenchyma in rats and mice. TNC knockout suppressed EBI in terms of brain edema, blood-brain barrier disruption, neuronal apoptosis and neuroinflammation, associated with the inhibition of post-SAH activation of mitogen-activated protein kinases and nuclear factor-kappa B in mice. In a clinical setting, more severe SAH increases more TNC in cerebrospinal fluid and peripheral blood, which could be a surrogate marker of EBI and predict DCI development and outcomes. In addition, cilostazol, a selective inhibitor of phosphodiesterase type III that is a clinically available anti-platelet agent and is known to suppress TNC induction, dose-dependently inhibited delayed cerebral infarction and improved outcomes in a pilot clinical study. Thus, further studies may facilitate application of TNC as biomarkers for non-invasive diagnosis or assessment of EBI and DCI, and lead to development of a molecular target drug against TNC, contributing to the improvement of post-SAH outcomes.

Tenascin-C accelerates adverse ventricular remodelling after myocardial infarction by modulating macrophage polarization.

AIMS: Tenascin-C (TN-C) is an extracellular matrix protein undetected in the normal adult heart, but expressed in several heart diseases associated with inflammation. We previously reported that serum TN-C levels of myocardial infarction (MI) patients were elevated during the acute stage, and that patients with high peak TN-C levels were at high risk of left ventricular (LV) remodelling and poor outcome, suggesting that TN-C could play a significant role in the progression of ventricular remodelling. However, the detailed molecular mechanisms associated with this process remain unknown. We aimed to elucidate the role and underlying mechanisms associated with TN-C in adverse remodelling after MI. METHODS AND RESULTS: MI was induced by permanent ligation of the coronary artery of TN-C knockout (TN-C-KO) and wild type (WT) mice. In WT mice, TN-C was expressed at the borders between intact and necrotic areas, with a peak at 3 days post-MI and observed in the immediate vicinity of infiltrating macrophages. TN-C-KO mice were protected from ventricular adverse remodelling as evidenced by a higher LV ejection fraction as compared with WT mice (19.0 ± 6.3% vs. 10.6 ± 4.4%; P < 0.001) at 3 months post-MI. During the acute phase, flow-cytometric analyses showed a decrease in F4/80+CD206lowCD45+ M1 macrophages and an increase in F4/80+CD206highCD45+ M2 macrophages in the TN-C-KO heart. To clarify the role of TN-C on macrophage polarization, we examined the direct effect of TN-C on bone marrow-derived macrophages in culture, observing that TN-C promoted macrophage shifting into an M1 phenotype via Toll-like receptor 4 (TLR4). Under M2-skewing conditions, TN-C suppressed the expression of interferon regulatory factor 4, a key transcription factor that controls M2-macrophage polarization, via TLR4, thereby inhibiting M2 polarization. CONCLUSION: These results suggested that TN-C accelerates LV remodelling after MI, at least in part, by modulating M1/M2-macrophage polarization.

Successful Inflammation Imaging of Non-Human Primate Hearts Using an Antibody Specific for Tenascin-C.

Inflammation after myocardial infarction (MI) may be a major factor influencing ventricular remodeling, leading to congestive heart failure and arrhythmia. Therefore, inflammation in the heart needs to be monitored. Tenascin-C (TNC) is an extracellular matrix molecule not normally expressed, but it is strongly upregulated when associated with active inflammation. Based on this characteristic, we successfully imaged in vivo inflammatory lesions in rat models using 111Indium (111In)-labeled anti-TNC antibodies. The aim of the present study was to further assess the applicability of this molecular imaging probe to detect inflammatory activity in primate hearts.We generated an MI model of cynomolgus monkeys (Macaca fascicularis) by coronary artery ligation and performed dual-isotope single-photon emission computed tomography (SPECT) imaging with an 111In-labeled anti-TNC antibody Fab' fragment (111In-TNC Fab') and 99mtechnetium methoxy-isobutyl isonitrile (99mTc-MIBI). Dual autoradiography was used to compare the uptake of 111In-TNC Fab' with histology and immunostaining for TNC. Dual-isotope SPECT showed the regional myocardial uptake of 111In-TNC Fab' complementary to a defect in the perfusion image by 99mTc-MIBI. The high radioactivity of 111In-TNC Fab' by autoradiography corresponded to immunostaining for TNC, which was observed in inflammatory lesions at the border zone between the infarcted and non-infarcted areas of the left ventricle and at the epi/pericarditis lesions of the right ventricle. These results demonstrate the potential of 111In-TNC-Fab' imaging to monitor myocardial injury and inflammation and suggest the feasibility of the non-invasive detection of cardiac inflammation following acute MI in a preclinical stage before testing in humans.

Clinical Significance of Histological Effect and Intratumor Stromal Expression of Tenascin-C in Resected Specimens After Chemoradiotherapy for Initially Locally Advanced Unresectable Pancreatic Ductal Adenocarcinoma.

OBJECTIVES: Tenascin-C (TN-C) is an extracellular matrix protein that is up-regulated in pancreatic ductal adenocarcinoma (PDAC) stroma and associated with tumor invasion. We examined intratumor stromal expression of TN-C in resected specimens and the histologic effect of chemoradiotherapy (CRT) as prognostic indicators in initially locally advanced unresectable (UR-LA) PDAC. METHODS: Among 110 UR-LA PDAC patients enrolled in the CRT protocol from February 2005 to December 2015, 46 who underwent curative-intent resection were classified as high (tumor destruction >50%) and low (≤50%) responders according to the Evans grading system. Tenascin-C expression was immunohistologically evaluated in all patients except one with complete response. RESULTS: The 12 high responders achieved a significantly higher R0 rate than did the 34 low responders (83.3 vs 47.1%), but disease-specific survival (DSS) time was not significantly different (median survival time, 29.8 vs 21.0 months). Tenascin-C expression was inversely correlated with histologic effect of CRT. The 22 patients with negative TN-C had significantly longer DSS time than did the 23 with positive TN-C (29.3 vs 17.1 months). In multivariate analysis, only TN-C expression was a significant prognostic factor for DSS. CONCLUSIONS: Intratumor stromal expression of TN-C is a strong prognostic indicator in UR-LA PDAC patients with resection after CRT.

Deficiency of Tenascin-C Alleviates Neuronal Apoptosis and Neuroinflammation After Experimental Subarachnoid Hemorrhage in Mice.

Tenascin-C (TNC), a matricellular protein, is upregulated in brain parenchyma after experimental subarachnoid hemorrhage (SAH). Recent studies emphasize that early brain injury (EBI) should be overcome to improve post-SAH outcomes. The aim of this study was to investigate effects of TNC knockout (TNKO) on neuronal apoptosis and neuroinflammation, both of which are important constituents of EBI after SAH. C57BL/6 wild-type (WT) mice or TNKO mice underwent sham or filament perforation SAH modeling. Twenty-five WT mice and 25 TNKO mice were randomly divided into sham+WT (n = 10), sham+TNKO (n = 8), SAH+WT (n = 15), and SAH+TNKO (n = 17) groups. Beam balance test, neurological score, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, immunostaining of Toll-like receptor 4 (TLR4), and Western blotting were performed to evaluate neurobehavioral impairments, neuronal apoptosis, and neuroinflammation at 24 h post-SAH. Deficiency of TNC significantly alleviated post-SAH neurobehavioral impairments and neuronal apoptosis. The protective effects of TNKO on neurons were associated with the inhibition of a caspase-dependent apoptotic pathway, which was at least partly mediated by TLR4/nuclear factor-κB/interleukin-1ß and interleukin-6 signaling cascades. This study first provided the direct evidence that TNC causes post-SAH neuronal apoptosis and neuroinflammation, potentially leading to the development of a new molecular targeted therapy against EBI.

Peritoneal Dialysis Fluid-Induced Fragmentation of Golgi Apparatus as a Biocompatibility Marker.

In vitro biocompatibility assessments that consider physiologically appropriate conditions of cell exposure to peritoneal dialysis fluids (PDFs) are still awaited. In this study, we found that fragmentation of Golgi apparatus occurred in a pH-dependent manner within 30-min exposure to five distinct commercially available PDFs, which showed no marked difference in their effects on cell viability in the conventional MTT assay. Fluorescence microscopy analysis of labeling antibody against cis-Golgi protein GM130 indicated that the stacked cisternal structure was maintained in the perinuclear area of both M199 culture medium and a neutral-pH PDF groups. However, this specific structure became partially disassembled over time even in a neutral-pH PDF, and fragmentation was markedly enhanced in cells exposed to neutralized-pH PDFs in correspondence with their intracellular pH; moreover, in acidic PDFs, Golgi staining was diffuse and scattered in the entire cytoplasm and showed partial aggregation. The Golgi fragmentation markedly observed with the neutralized PDFs could be reversed by replacing either the media with a neutral-pH medium or a mixture of PDF and PD effluent (PDF) in a gradient manner mimicking clinical conditions. Furthermore, although weaker than pH effect, notable effects of other PDF-related factors were also observed after 30-min exposure to pH-adjusted PDFs. Lastly, the results of studies conducted using MAPK/SAPK inhibitors indicated that the mechanism underlying the Golgi fragmentation described here differs from that associated with the fragmentation that occurs at the G2/M checkpoint in the cell cycle. We conclude that Golgi fragmentation is suitable for rapid biocompatibility assessment of PDF not only because of its strong pH dependence but also because the fragmentation is recognizably affected by PDF constituents.

Tenascin-C Prevents Articular Cartilage Degeneration in Murine Osteoarthritis Models.

Objective The objective of this study was to determine whether intra-articular injections of tenascin-C (TNC) could prevent cartilage damage in murine models of osteoarthritis (OA). Design Fluorescently labeled TNC was injected into knee joints and its distribution was examined at 1 day, 4 days, 1 week, 2 weeks, and 4 weeks postinjection. To investigate the effects of TNC on cartilage degeneration after surgery to knee joints, articular spaces were filled with 100 µg/mL (group I), 10 µg/mL (group II) of TNC solution, or control (group III). TNC solution of 10 µg/mL was additionally injected twice after 3 weeks (group IV) or weekly after 1 week, 2 weeks, and 3 weeks (group V). Joint tissues were histologically assessed using the Mankin score and the modified Chambers system at 2 to 8 weeks after surgery. Results Exogenous TNC was maintained in the cartilage and synovium for 1 week after administration. Histological scores in groups I and II were better than scores in group III at 4 and 6 weeks, but progressive cartilage damage was seen in all groups 8 weeks postoperatively. Sequential TNC injections (groups IV and V) showed significantly better Mankin score than single injection (group II) at 8 weeks. Conclusion TNC administered exogenously remained in the cartilage of knee joints for 1 week, and could decelerate articular cartilage degeneration in murine models of OA. We also showed that sequential administration of TNC was more effective than a single injection. TNC could be an important molecule for prevention of articular cartilage damage.

Role of tenascin-C in articular cartilage.

Tenascin-C (TN-C) is a glycoprotein component of the extracellular matrix (ECM). TN-C consists of four distinct domains, including the tenascin assembly domain, epidermal growth factor-like repeats, fibronectin type III-like repeats, and the fibrinogen-like globe (FBG) domain. This review summarizes the role of TN-C in articular cartilage. Expression of TN-C is associated with the development of articular cartilage but markedly decreases during maturation of chondrocytes and disappears almost completely in adult articular cartilage. Increased expression of TN-C has been found at diseased cartilage and synovial sites in osteoarthritis (OA) and rheumatoid arthritis (RA). TN-C is increased in the synovial fluid in patients with OA and RA. In addition, serum TN-C is elevated in RA patients. TN-C could be a useful biochemical marker for joint disease. The addition of TN-C results in different effects among TN-C domains. TN-C fragments might be endogenous inducers of cartilage matrix degradation; however, full-length TN-C could promote cartilage repair and prevent cartilage degeneration. The deficiency of TN-C enhanced cartilage degeneration in the spontaneous OA in aged joints and surgical OA model. The clinical significance of TN-C effects on cartilage is not straightforward.

Effects of Tenascin-C Knockout on Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage in Mice.

A matricellular protein tenascin-C (TNC) has been suggested to play a role in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH), but the direct evidence remains lacking. In this study, we examined effects of TNC knockout (TNKO) on cerebral vasospasm after experimental SAH in mice. C57BL/6 wild-type (WT) or TNKO mice were subjected to SAH by endovascular puncture. Ten WT and ten TNKO mice were randomized to WT sham (n = 4), TNKO sham (n = 4), WT SAH (n = 6), and TNKO SAH (n = 6) groups. In addition to neurobehavioral impairments and severity of SAH, cerebral vasospasm was assessed by morphometric measurements of the left internal carotid artery (ICA). Infiltration of inflammatory cells in the subarachnoid periarterial space was also assessed, and expressions of TNC and mitogen-activated protein kinases (MAPKs) in the ICA were immunohistochemically evaluated at 24 h post-surgery. TNC was induced in the smooth muscle cell layers and the adventitia in the spastic ICAs as well as the periarterial inflammatory cells in WT SAH mice. Compared with WT SAH mice, TNKO SAH mice showed better neurological scores and less severe cerebral vasospasm, as well as fewer inflammatory cell infiltration in the periarterial space. Post-SAH activation of MAPKs in the smooth muscle cell layers of the ICAs was also prevented in TNKO SAH mice. The findings in the present study suggest that TNC causes the development of cerebral vasospasm via pro-inflammatory effects and activation of MAPKs.

Tadalafil Improves L-NG-Nitroarginine Methyl Ester-Induced Preeclampsia With Fetal Growth Restriction-Like Symptoms in Pregnant Mice.

BACKGROUND: We investigated the efficacy and mechanisms of tadalafil, a selective phosphodiesterase 5 inhibitor, in treating preeclampsia (PE) with fetal growth restriction (FGR) using L-NG-nitroarginine methyl ester (L-NAME)-induced PE with FGR in pregnant mice as our experimental model. METHODS: C57BL/6 mice were divided into 2 groups 11 days postcoitum (d.p.c.). A control group of dams (C dam) received 0.5% carboxymethylcellulose (CMC). A L-NAME-treated group received 1 mg/ml L-NAME dissolved in CMC. The L-NAME-treated dams were divided into 2 subgroups 13 d.p.c. One subgroup continued to receive L-NAME (L dams). The other subgroup received L-NAME with 0.08 mg/ml tadalafil suspended in CMC (TL dams). Maternal systolic blood pressure (SBP) and proteinuria were assessed 16 d.p.c. Fetal weight was recorded, and placentas and maternal kidneys were collected 17 d.p.c. RESULTS: Maternal SBP, proteinuria, and fetal weight were improved for TL dams compared to L dams. The placental concentration of placental growth factor (PlGF) was higher for TL dams than for the C and L dams. The placental maternal blood sinuses of L dams were narrower than those of C dams, but those of TL dams improved to a similar width as C dams. Glomerular oxidative stress was ameliorated in TL dams compared to L dams. CONCLUSIONS: Tadalafil dilates the placental maternal blood sinuses, which leads to increase PlGF production, and contributes to facilitate fetal growth and improve maternal SBP. Moreover, tadalafil ameliorates glomerular damage by reducing oxidative stress. These results suggest that tadalafil is a candidate for treatment of PE with FGR.