Notch ligands are biomarkers of anti-TNF response in RA patients

Notch and its ligands play a critical role in rheumatoid arthritis (RA) pathogenesis. Hence, studies were conducted to delineate the functional significance of the Notch pathway in RA synovial tissue (ST) cells and the influence of RA therapies on their expression. Morphological studies reveal that JAG1, DLL4, and Notch1 are highly enriched in RA ST lining and sublining CD68+CD14+ MΦs. JAG1 and DLL4 transcription is jointly upregulated in RA MΦs reprogrammed by TLR4/5 ligation and TNF, whereas Syntenin-1 exposure expands JAG1, DLL4, and Notch1 expression levels in these cells. Single-cell RNA-seq data exhibit that JAG1 and Notch3 are overexpressed on all fibroblast-like synoviocyte (FLS) subpopulations, in parallel, JAG2, DLL1, and Notch1 expression levels are modest on RA FLS and are predominately potentiated by TLR4 ligation. Intriguingly, JAG1, DLL1/4, and Notch1/3 are presented on RA endothelial cells, and their expression is mutually reconfigured by TLR4/5 ligation in the endothelium. Synovial JAG1/JAG2/DLL1 or Notch1/3 transcriptomes were unchanged in patients who received disease-modifying anti-rheumatic drugs (DMARDs) or IL-6R Ab therapy regardless of disease activity score. Uniquely, RA MΦs and endothelial cells rewired by IL-6 displayed DLL4 transcriptional upregulation, and IL-6R antibody treatment disrupted RA ST DLL4 transcription in good responders compared to non-responders or moderate responders. Nevertheless, the JAG1/JAG2/DLL1/DLL4 transcriptome was diminished in anti-TNF good responders with myeloid pathotype and was unaltered in the fibroid pathotype except for DLL4. Taken together, our findings suggest that RA myeloid Notch ligands can serve as markers for anti-TNF responsiveness and trans-activate Notch receptors expressed on RA FLS and/or endothelial cells.

Metabolic reprogramming by Syntenin-1 directs RA FLS and endothelial cell-mediated inflammation and angiogenesis

A novel rheumatoid arthritis (RA) synovial fluid protein, Syntenin-1, and its receptor, Syndecan-1 (SDC-1), are colocalized on RA synovial tissue endothelial cells and fibroblast-like synoviocytes (FLS). Syntenin-1 exacerbates the inflammatory landscape of endothelial cells and RA FLS by upregulating transcription of IRF1/5/7/9, IL-1β, IL-6, and CCL2 through SDC-1 ligation and HIF1α, or mTOR activation. Mechanistically, Syntenin-1 orchestrates RA FLS and endothelial cell invasion via SDC-1 and/or mTOR signaling. In Syntenin-1 reprogrammed endothelial cells, the dynamic expression of metabolic intermediates coincides with escalated glycolysis along with unchanged oxidative factors, AMPK, PGC-1α, citrate, and inactive oxidative phosphorylation. Conversely, RA FLS rewired by Syntenin-1 displayed a modest glycolytic-ATP accompanied by a robust mitochondrial-ATP capacity. The enriched mitochondrial-ATP detected in Syntenin-1 reprogrammed RA FLS was coupled with mitochondrial fusion and fission recapitulated by escalated Mitofusin-2 and DRP1 expression. We found that VEGFR1/2 and Notch1 networks are responsible for the crosstalk between Syntenin-1 rewired endothelial cells and RA FLS, which are also represented in RA explants. Similar to RA explants, morphological and transcriptome studies authenticated the importance of VEGFR1/2, Notch1, RAPTOR, and HIF1α pathways in Syntenin-1 arthritic mice and their obstruction in SDC-1 deficient animals. Consistently, dysregulation of SDC-1, mTOR, and HIF1α negated Syntenin-1 inflammatory phenotype in RA explants, while inhibition of HIF1α impaired synovial angiogenic imprint amplified by Syntenin-1. In conclusion, since the current therapies are ineffective on Syntenin-1 and SDC-1 expression in RA synovial tissue and blood, targeting this pathway and its interconnected metabolic intermediates may provide a novel therapeutic strategy.

Syntenin-1-mediated arthritogenicity is advanced by reprogramming RA metabolic macrophages and Th1 cells

OBJECTIVES

Syntenin-1, a novel endogenous ligand, was discovered to be enriched in rheumatoid arthritis (RA) specimens compared with osteoarthritis synovial fluid and normal synovial tissue (ST). However, the cellular origin, immunoregulation and molecular mechanism of syntenin-1 are undescribed in RA.

METHODS

RA patient myeloid and lymphoid cells, as well as preclinical models, were used to investigate the impact of syntenin-1/syndecan-1 on the inflammatory and metabolic landscape.

RESULTS

Syntenin-1 and syndecan-1 (SDC-1) co-localise on RA ST macrophages (MΦs) and endothelial cells. Intriguingly, blood syntenin-1 and ST SDC-1 transcriptome are linked to cyclic citrullinated peptide, erythrocyte sedimentation rate, ST thickness and bone erosion. Metabolic CD14+CD86+GLUT1+MΦs reprogrammed by syntenin-1 exhibit a wide range of proinflammatory interferon transcription factors, monokines and glycolytic factors, along with reduced oxidative intermediates that are downregulated by blockade of SDC-1, glucose uptake and/or mTOR signalling. Inversely, IL-5R and PDZ1 inhibition are ineffective on RA MΦs-reprogrammed by syntenin-1. In syntenin-1-induced arthritis, F4/80+iNOS+RAPTOR+MΦs represent glycolytic RA MΦs, by amplifying the inflammatory and glycolytic networks. Those networks are abrogated in SDC-1-/- animals, while joint prorepair monokines are unaffected and the oxidative metabolites are moderately replenished. In RA cells and/or preclinical model, syntenin-1-induced arthritogenicity is dependent on mTOR-activated MΦ remodelling and its ability to cross-regulate Th1 cells via IL-12 and IL-18 induction. Moreover, RA and joint myeloid cells exposed to Syntenin-1 are primed to transform into osteoclasts via SDC-1 ligation and RANK, CTSK and NFATc1 transcriptional upregulation.

CONCLUSION

The syntenin-1/SDC-1 pathway plays a critical role in the inflammatory and metabolic landscape of RA through glycolytic MΦ and Th1 cell cross-regulation (graphical abstract).

The effect of induced lymphatic circulation on lymphangiogenesis and inflammatory mediators in rats with adjuvant induced arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease involving dysfunctional lymphatic circulation leading to edema. The adjuvant-induced arthritis (AIA) rat model was used to study the effect of lymphatic pump treatment (LPT) on the expression levels of inflammatory cytokines and lymphangiogenesis within the draining popliteal lymph nodes (PLN). PLN from both control and LPT treatment groups were harvested, and their cDNA were analyzed by qPCR to determine the levels of cytokines, VEGF-C, and VEGFR-3. Additionally, immunohistochemistry was used to visualize the expression of VEGF-C and VEGFR-3 and flow cytometry was used to quantify leukocyte cell types in the PLN. The LPT group showed a decrease in ankle circumference and arthritis grade a few days after the initiation of treatment. Flow cytometry of popliteal lymph nodes showed an increase in CD8, CD4, and CD3 cells in arthritic rats, however cell populations were not significantly different between treatment groups. The qPCR data indicated that the LPT group had a slight reduction in levels of IL-17a, IL-4, IL-6, and IL-1β. IHC showed that the PLN from the LPT group had the highest expression area of VEGF-C and the lowest expression area of VEGFR-3 compared to control. In conclusion, The LPT group showed a reduction in ankle circumference and arthritis score, suggesting that LPT helped alleviate edema and inflammation. When compared to control, the LPT group had lower expression of pro-inflammatory cytokines and elevated levels of VEGF-C, an important lymphatic vessel growth factor, in PLN. Thus, the data suggests that LPT may elevate the swelling and inflammation in rat AIA through the reduction of inflammatory cytokines and the elevation of a lymphatic growth factor.

IRAK4 inhibitor mitigates joint inflammation by rebalancing metabolism malfunction in RA macrophages and fibroblasts

Recent studies show a connection between glycolysis and inflammatory response in rheumatoid arthritis (RA) macrophages (MΦs) and fibroblasts (FLS). Yet, it is unclear which pathways could be targeted to rebalance RA MΦs and FLS metabolic reprogramming. To identify novel targets that could normalize RA metabolic reprogramming, TLR7-mediated immunometabolism was characterized in RA MΦs, FLS and experimental arthritis. We uncovered that GLUT1, HIF1α, cMYC, LDHA and lactate were responsible for the TLR7-potentiated metabolic rewiring in RA MΦs and FLS, which was negated by IRAK4i. While in RA FLS, HK2 was uniquely expanded by TLR7 and negated by IRAK4i. Conversely, TLR7-driven hypermetabolism, non-oxidative PPP (CARKL) and oxidative phosphorylation (PPARγ) were narrowly dysregulated in TLR7-activated RA MΦs and FLS and was reversed by IRAK4i. Consistently, IRAK4i therapy disrupted arthritis mediated by miR-Let7b/TLR7 along with impairing a broad-range of glycolytic intermediates, GLUT1, HIF1α, cMYC, HK2, PFKFB3, PKM2, PDK1 and RAPTOR. Notably, inhibition of the mutually upregulated glycolytic metabolites, HIF1α and cMYC, was capable of mitigating TLR7-induced inflammatory imprint in RA MΦs and FLS. In keeping with IRAK4i, treatment with HIF1i and cMYCi intercepted TLR7-enhanced IRF5 and IRF7 in RA MΦs, distinct from RA FLS. Interestingly, in RA MΦs and FLS, IRAK4i counteracted TLR7-induced CARKL reduction in line with HIF1i. Whereas, cMYCi in concordance with IRAK4i, overturned oxidative phosphorylation via PPARγ in TLR7-activated RA MΦs and FLS. The blockade of IRAK4 and its interconnected intermediates can rebalance the metabolic malfunction by obstructing glycolytic and inflammatory phenotypes in RA MΦs and FLS.

Abstract 5997: Increased connexin 43 expression and gap junction communication correlates with invasion following reduced glucose metabolism in breast cancer cells

Dysregulation of gap junction intercellular communication (GJIC) is a common feature during cancer progression. GJIC is a means of direct cell-cell communication mediated by regulated membrane channels composed of connexin proteins. This communication is frequently lost between primary tumor cells but may be upregulated at secondary metastatic sites with stromal cells. Control of this process by cancer cells has been shown to facilitate aggressive qualities both in vitro and in vivo. During the process of metastasis, cells encounter numerous metabolic challenges that must be overcome, particularly during growth of primary tumors. In this study, we set out to evaluate if changes to cancer cell metabolism affect GJIC in breast cancer cells. To address this question, we generated a metabolic variant of the MDA-MB-231 cell line conditioned to grow in glucose-limiting conditions. These cells were grown in FBS supplemented RPMI with <0.130mM glucose compared to 2mM in control conditions for more than 4 weeks. Substantial cell death over this time revealed a small population of cells capable of surviving in glucose reduced conditions. Growth of these cells normalized following a period of quiescence and exhibited stable viability and proliferative capacity. Following STR validation, these cells were designated MDA-MB-231LG for their ability to grow in low glucose media. MDA-MB-231LG exhibited a larger and more rounded morphologic appearance with formation of strong cell-cell contacts as demonstrated by scanning electron microscopy in contrast to parental cells which showed a higher degree of membrane overlap. Further comparison of the two cell lines through western blot and immunofluorescence analysis of connexin 43, a major connexin expressed in breast tissue, revealed higher levels in MDA-MB-231LG and increased membrane localization. Using a double label dye transfer technique, the gap junction permeable fluorescent dye calcein showed increased movement from CM-DiI labeled donor cells into neighboring cells in MDA-MB-231LG indicating functional gap junction coupling while MDA-MB-231 had little to no dye movement. To evaluate phenotypic qualities, both cell lines were grown in Matrigel and MDA-MB-231LG displayed increased stellate morphology. Use of a Matrigel invasion chamber assay confirmed the increased invasive qualities with significantly more MDA-MB-231LG invading through the lower portion of the membrane compared to MDA-MB-231 parental cells. Our data demonstrate a clear upregulation of gap junction activity following metabolic adaptation to reduced glucose availability. It also suggests a possible connection between GJIC and invasive qualities in breast cancer cells and may represent an inducible phenotype that occurs in primary tumors when tumor growth limits blood vessel penetration and nutrient availability.

Citation Format: Jennifer C. Jones, Amanda M. Miceli, Mary M. Chaudhry, Mallika A. Jai, Romel N. Pancho, Alan Lazzar, Bradley S. Taylor, Vishnupriya Bodempudi, Prarthana P. Jain, Sheeri Hanjra, Alexander E. Urban, Brian Zanotti, Ellen K. Kohlmeir, Thomas M. Bodenstine. Increased connexin 43 expression and gap junction communication correlates with invasion following reduced glucose metabolism in breast cancer cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5997.

IRAK4 inhibition: a promising strategy for treating RA joint inflammation and bone erosion

Flares of joint inflammation and resistance to currently available biologic therapeutics in rheumatoid arthritis (RA) patients could reflect activation of innate immune mechanisms. Herein, we show that a TLR7 GU-rich endogenous ligand, miR-Let7b, potentiates synovitis by amplifying RA monocyte and fibroblast (FLS) trafficking. miR-Let7b ligation to TLR7 in macrophages (MΦs) and FLSs expanded the synovial inflammatory response. Moreover, secretion of M1 monokines triggered by miR-Let7b enhanced Th1/Th17 cell differentiation. We showed that IRAK4 inhibitor (i) therapy attenuated RA disease activity by blocking TLR7-induced M1 MΦ or FLS activation, as well as monokine-modulated Th1/Th17 cell polarization. IRAK4i therapy also disrupted RA osteoclastogenesis, which was amplified by miR-Let7b ligation to joint myeloid TLR7. Hence, the effectiveness of IRAK4i was compared with that of a TNF inhibitor (i) or anti-IL-6R treatment in collagen-induced arthritis (CIA) and miR-Let7b-mediated arthritis. We found that TNF or IL-6R blocking therapies mitigated CIA by reducing the infiltration of joint F480⁺iNOS⁺ MΦs, the expression of certain monokines, and Th1 cell differentiation. Unexpectedly, these biologic therapies were unable to alleviate miR-Let7b-induced arthritis. The superior efficacy of IRAK4i over anti-TNF or anti-IL-6R therapy in miR-Let7b-induced arthritis or CIA was due to the ability of IRAK4i therapy to restrain the migration of joint F480⁺iNOS⁺ MΦs, vimentin⁺ fibroblasts, and CD3⁺ T cells, in addition to negating the expression of a wide range of monokines, including IL-12, MIP2, and IRF5 and Th1/Th17 lymphokines. In conclusion, IRAK4i therapy may provide a promising strategy for RA therapy by disconnecting critical links between inflammatory joint cells.

Induced lymphatic circulation decreases IL-17 expression in the lymph nodes of rats in adjuvant-induced arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic inflammation mediated by Th-17 cells. Rat adjuvant-induced arthritis (AIA) is a Th-17-dependent RA model with dysfunctional lymphatic circulation. We hypothesized that induction of lymphatic circulation would attenuate arthritic inflammation. We utilized Lymphatic Pump Treatment (LPT), an osteopathic lymphatic manipulation, to determine if inducing lymphatic flow would alleviate arthritic inflammation. LPT was accomplished on AIA rats by gradually increasing compression on the chest wall for 5 seconds followed by a rapid release. This technique was performed on the rats for 1 minute 3X/day over 7 consecutive days following the onset of measurable inflammation on day 14 post adjuvant injection. Ankle caliper measurements, articular index scoring, popliteal lymph nodes, peripheral blood, and spleens were collected. The LPT-treated rats fell into two groups. LPT responders and non-responders. LPT responders had significantly reduced inflammation (as determined by both in ankle circumference and index scoring). These therapeutically treated animals also had significantly decreased IL-17 expression in their draining popliteal lymph nodes. These results along with our previous findings indicate that LPT can reduce arthritis, alter lymphocyte trafficking and differentiation in secondary lymphoid organs during inflammation. These data suggest that induced lymphatic circulation using osteopathic manipulation may serve as a therapy for chronic inflammation in autoimmune disorders and may also be an enhancement to current treatments.

Impact of Epstein-Barr Virus LMP2A-dependent BTK/STAT3 activation on resting and activated murine B cells

Epstein-Barr virus (EBV) latently infects over 90% of the population and is associated with the development of numerous autoimmune diseases and B cell lymphomas. Therefore, understanding the impact of latency proteins on B cell survival and function is vital. One EBV latency protein, LMP2A, acts as a BCR mimic to promote B cell survival, increase B cell activation, and accelerate tumor development in murine mouse models. Our laboratory identified that LMP2A activates the PI3K/BTK/STAT3 pathway in human B cell lymphomas to increase IL-10 production that promotes survival. However, the ability of LMP2A to activate BTK and STAT3 in non-transformed B cells is unknown. To test this possibility, we returned to the LMP2A transgenic mouse model as a source of resting B cells that express LMP2A. To determine if LMP2A activates STAT3 in the mouse model, resting B cells from wildtype and LMP2A-transgenic mice were isolated and STAT3 phosphorylation was assessed by Western blot analysis. Our data indicate that LMP2A-postitive B cells express higher levels of phosphorylated STAT3 than wildtype controls. We further analyzed whether the LMP2A-dependent activation of STAT3 resulted in an increase in STAT3-dependent targets. Flow cytometric analysis indicates that the addition of STAT3 inhibitors to activated LMP2A-expressing B cells blocked the LMP2A-dependent increase in STAT3 targets in comparison to wildtype controls. These data suggest that LMP2A increases the activation of the oncogene STAT3 in resting B cells, which may contribute to the development of EBV-associated tumors and autoimmune diseases.

CCL21/CCR7 signaling in macrophages promotes joint inflammation and Th17-mediated osteoclast formation in rheumatoid arthritis

In rheumatoid arthritis (RA), synovial tissue abundantly expresses CCL21, a chemokine strongly associated with RA susceptibility. In this study, we aimed to characterize the functional significance of CCL21/CCR7 signaling in different phases of RA pathogenesis. We determined that CCR7 is a hallmark of RA M1 synovial fluid (SF) macrophages, and its expression in RA monocytes and in vitro differentiated macrophages is closely associated with disease activity score (DAS28). In early stages of RA, monocytes infiltrate the synovial tissue. However, blockade of SF CCL21 or CCR7 prevents RA SF-mediated monocyte migration. CCR7 expression in the newly migrated macrophages can be accentuated by LPS and IFNγ and suppressed by IL-4 treatment. We also uncovered that CCL21 stimulation increases the number of M1-polarized macrophages (CD14+CD86+), resulting in elevated transcription of IL-6 and IL-23. These CCL21-induced M1 cytokines differentiate naïve T cells to Th17 cells, without affecting Th1 cell polarization. In the erosive stages of disease, CCL21 potentiates RA osteoclastogenesis through M1-driven Th17 polarization. Disruption of this intricate crosstalk, by blocking IL-6, IL-23, or IL-17 function, impairs the osteoclastogenic capacity of CCL21. Consistent with our in vitro findings, we establish that arthritis mediated by CCL21 expands the joint inflammation to bone erosion by connecting the differentiation of M1 macrophages with Th17 cells. Disease progression is further exacerbated by CCL21-induced neovascularization. We conclude that CCL21 is an attractive novel target for RA therapy, as blockade of its function may abrogate erosive arthritis modulated by M1 macrophages and Th17 cell crosstalk.

Increased lymphatic circulation decreases CD4 counts in the lymph nodes of rats in adjuvant-induced arthritis

Rheumatoid arthritis (RA) is a disorder characterized by chronic inflammation. Rat adjuvant-induced arthritis (AIA) is a RA model with dysfunctional lymphatic circulation. We hypothesized that increasing lymphatic circulation would decrease arthritic inflammation. In order to determine if increasing lymphatic flow would decrease arthritic inflammation, we utilized osteopathic lymphatic manipulation (Lymphatic pump treatment (LPT)) during either the onset or during arthritis. LPT was performed by gradually increasing compression on the rat chest wall over 5 seconds followed by rapid release for 5 seconds. This technique was repeated for 1 minute 3X/day for 7 consecutive days either before the onset of inflammation (preventative treatment) or after measurable inflammation (therapeutic treatment). Articular index scoring, ankle caliper measurements, and peripheral blood, spleens, and popliteal lymph nodes were collected. In both the preventative and therapeutic studies, the LPT-treated rats had reduced inflammation. Therapeutically treated animals also had significantly decreased CD4+ lymphocytes in the draining popliteal lymph nodes, with increases in CD4+ cells in the spleen. These results suggest that LPT can reduce arthritis and alter lymphocyte trafficking in secondary lymphoid organs during inflammation. These data suggest that forced lymphatic circulation through osteopathic manipulation may serve to enhance current treatments to decrease inflammatory diseases.

A synthetic glycosaminoglycan mimetic blocks HSV-1 infection in human iris stromal cells

Herpes simplex virus type-1 (HSV-1) is a significant pathogen that affects vision by targeting multiple regions in the human eye including iris. Using a focused library of synthetic non-saccharide glycosaminoglycan mimetics (NSGMs), we identified sulfated pentagalloylglucoside (SPGG) as a potent inhibitor of HSV-1 entry and cell-to-cell spread in the primary cultures of human iris stromal (HIS) cells isolated from eye donors. Using in vitro β-galactosidase reporter assay and plaque reduction assay, SPGG was found to inhibit HSV-1 entry in a dosage-dependent manner (IC₅₀ ∼6.0 μM). Interestingly, a pronounced inhibition in HSV-1 entry and spread was observed in HIS cells, or a cell line expressing specific gD-receptor, when virions were pre-treated with mimetics suggesting a possible interaction between SPGG and the HSV-1 glycoprotein. To examine the significance of gD-SPGG interaction, HIS cells were pretreated with SPGG, which showed a significant reduction in gD binding. Taken together, our results provide strong evidence of SPGG being a novel viral entry inhibitor against ocular HSV infection.

Preclinical evaluation of the Aurora kinase inhibitors AMG 900, AZD1152-HQPA, and MK-5108 on SW-872 and 93T449 human liposarcoma cells

Liposarcoma is a malignant soft tissue tumor that originates from adipose tissue and is one of the most frequently diagnosed soft tissue sarcomas in humans. There is great interest in identifying novel chemotherapeutic options for treating liposarcoma based upon molecular alterations in the cancer cells. The Aurora kinases have been identified as promising chemotherapeutic targets based on their altered expression in many human cancers and cellular roles in mitosis and cytokinesis. In this study, we investigated the effects of an Aurora kinase A inhibitor (MK-5108), an Aurora kinase B inhibitor (AZD1152-HQPA), and a pan-Aurora kinase inhibitor (AMG 900) on undifferentiated SW-872 and well-differentiated 93T449 human liposarcoma cells. Treatment of the SW-872 and 93T449 cells with MK-5108 (0-1000 nM), AZD1152-HQPA (0-1000 nM), and AMG 900 (0-1000 nM) for 72 h resulted in a dose-dependent decrease in the total viable cell number. Based upon the EC₅₀ values, the potency of the three Aurora kinase inhibitors in the SW-872 cells was as follows: AMG 900 (EC₅₀ = 3.7 nM) > AZD1152-HQPA (EC₅₀ = 43.4 nM) > MK-5108 (EC₅₀ = 309.0 nM), while the potency in the 93T449 cells was as follows: AMG 900 (EC₅₀ = 6.5 nM) > AZD1152-HQPA (EC₅₀ = 74.5 nM) > MK-5108 (EC₅₀ = 283.6 nM). The percentage of polyploidy after 72 h of drug treatment (0-1000 nM) was determined by propidium iodide staining and flow cytometric analysis. AMG 900 caused a significant increase in polyploidy starting at 25 nM in the SW-872 and 93T449 cells, and AZD1152-HQPA caused a significant increase starting at 100 nM in the SW-872 cells and 250 nM in the 93T449 cells. The Aurora kinase A inhibitor MK-5108 did not significantly increase the percentage of polyploid cells at any of the doses tested in either cell line. The expression of Aurora kinase A and B was evaluated in the SW-872 cells versus differentiated adipocytes and human mesenchymal stem cells by real-time RT-PCR and Western blot analysis. Aurora kinase A and B mRNA expression was significantly increased in the SW-872 cells versus the differentiated adipocytes and human mesenchymal stem cells. Western blot analysis revealed a ~ 48 kDa immunoreactive band for Aurora kinase A that was not present in the differentiated adipocytes or the human mesenchymal stem cells. A ~ 39 kDa immunoreactive band for Aurora kinase B was detected in the SW-872 cells, differentiated adipocytes, and human mesenchymal stem cells. A smaller immunoreactive band for Aurora kinase B was detected in the SW-872 cells but not in the differentiated adipocytes and human mesenchymal stem cells, and this may reflect the expression of a truncated splice variant of Aurora kinase B that has been associated with poor patient prognosis. The 93T449 cells demonstrated decreased expression of Aurora kinase A and B mRNA and protein compared to the SW-872 cells, and also expressed the truncated form of Aurora kinase B. The results of these in vitro studies indicate that Aurora kinase inhibitors should be further investigated as possible chemotherapeutic agents for human liposarcoma.

Evaluation of the pathogenesis of Chlamydia induced reactive arthritis

We hypothesized that reactive arthritis can be induced in the knees and ankles of wild-type C57BL/6 mice following infection with Chlamydia muridarum through the involvement of inflammatory mediators. Reactive arthritis is a chronic form of arthritis, which can also result in conjunctivitis and inflammation of the genital, urinary, or gastrointestinal systems. C. muridarum is a gram-negative obligate intracellular pathogen which can infect the epithelium of the cervix, urethra, and rectum. The exact pathological mechanism of reactive arthritis is unknown. It is understood to result from CD4+ and CD8+ T cells, and factors including TNF-alpha and perforin. Five groups of C57BL/6J mice were used including a positive control group, CD4+ T cells knockout mice, TNF-alpha knockout mice, perforin knockout mice and TNFRSF knockout mice. Mice from each group were intra-vaginally infected with 5×104 inclusion forming units of C. muridarum, marked as day 0. The mice were swabbed a few days after infection to confirm C. muridarum. The mice from each group were euthanized on day 7 and day 14, and sera was collected and analyzed for cytokine expression using an antibody array. Ankles collected from C57BL/6J positive control mice were histologically processed and graded to determine pathology. C57BL/6J positive control mice showed increased synovial lining thickening 14 days following infection. Cytokine expression from TNF-alpha knockout mice, CD4+ T cells knockout mice, perforin knockout mice, and TNFRSF knockout mice was generally reduced. The results show that chlamydial induced reactive arthritis can be detected in the ankles of C57BL/6J mice and suggest that TNF-alpha and CD4+ T cells may be involved in this inflammatory process.

From Diagnostic Imaging to Management of Bacterial Brain Abscesses

Advances in neuroradiological investigation have revolutionised the diagnosis and treatment of brain abscesses. CT and MR scans offer diagnostic information, disclosing the exact location, morphology and stage of infection. When these examinations fail to define the type of lesions, nuclear medicine can be called into play with scintigraphy using labelled autologous leukocytes performed with SPECT for differential diagnosis.

Once the diagnosis of brain abscess is established, management is based on neuroradiological findings such as abscess stage, size, localisation and number and clinical information such as source of infection and the general clinical conditions of the patient. Conservative management is confined to small lesions at the early stage in patients whose general clinical condition is good and stable and there are no signs of intracranial hypertension. Surgery is required to treat large abscesses when the patient's general condition is poor. Different procedures are available, endoscopic evacuation aided by stereotactic systems now being the method of choice with respect to traditional excision. Neuroradiological monitoring is necessary whatever the treatment option to assess outcome and possible recurrence.

L'ernia discale e lombare

La dissoluzione chimica del nucleo polposo (Chemonucleolisi) o la decompressione parziale meccanica automatica (Nucleoaspirazione discale) sono delle efficaci procedure terapeutiche che affiancano la terapia chirurgica nei pazienti affetti da conflitto disco-radicolare. Gli interventi percutanei debbono essere riservati alle sciatiche radicolari dopo insuccesso di terapie medica e fisioterapica. L'indicazione ottimale ai trattamenti percutanei è rappresentata da pazienti giovani, con corporatura atletica e breve durata della sintomatologia. Il momento fondamentale nella applicazione degli interventi percutanei è rappresentato dalle indicazioni che debbono essere rigorosamente definite in base a criteri di selezione clinica e neuroradiologica. Gli esami neuroradiologici di prima istanza che confermano il quesito clinico sono la tomografia assiale computerizzata o la tomografia a risonanza magnetica, ma l'esame basilare è sicuramente la discografia. La nostra esperienza, di oltre 900 dischi trattati, dimostra che la discografia è un esame irrinunciabile, in quanto precisa con sicurezza la posizione dell'ago, il contenimento o meno dell'ernia, le dimensioni, la continuità con il nucleo polposo ed eventuali controindicazioni.

A post-market surveillance analysis of the safety of hydroxyapatite-derived products as bone graft extenders or substitutes for spine fusion

OBJECTIVE

Iliac crest bone graft (ICBG) is considered the gold standard for spine surgical procedures to achieve a successful fusion, because of its known osteoinductive and osteoconductive properties. Considering its autogenous origin, the use of ICBG has not been associated to an increase of intraoperative or postoperative complications directly related to the surgery. However, complications related to the harvesting procedure and to the donor site morbidity have been largely reported in the literature, favoring the development of a wide range of alternative products to be used as bone graft extenders or substitutes for spine fusion. The family of ceramic-based bone grafts has been widely used and studied during the last years for spine surgical procedures in order to reduce the need for iliac crest bone grafting and the consequent morbidity associated to the harvesting procedures.

PATIENTS AND METHODS

We report here the results of a post-market surveillance analysis performed on four independent cohorts of patients (115 patients) to evaluate the safety of three different formulations of hydroxyapatite-derived products used as bone graft extenders/substitutes for lumbar arthrodesis.

RESULTS

No intraoperative or post-operative complications related to the use of hydroxyapatite-derived products were detected, during medium and long follow up period (minimum 12 months-maximum 5 years).

CONCLUSIONS

This post-market surveillance analysis evidenced the safety of ceramic products as bone graft extenders or substitutes for spine fusion. Moreover, the evidence of the safety of hydroxyapatite-derived products allows to perform clinical studies aimed at evaluating the fusion rates and the clinical outcomes of these materials as bone graft extenders/substitutes, in order to support their use as an alternative to ICBG for spine fusion.

Alleviation of joint inflammation by lymphatic pump treatment of rats with adjuvant-induced arthritis (CAM1P.163)

Rheumatoid arthritis (RA) is characterized by synovial inflammation, cytokine production and lymph node collapse. Lymphatic pump treatment (LPT) is an osteopathic manipulative treatment used to reduce edema through increasing lymphatic circulation. This study examined the therapeutic potential of LPT on rats with adjuvant-induced arthritis (AIA). We hypothesize that LPT would lessen joint inflammation through increasing lymphatic drainage resulting in the reduction of cytokines in synovial space. AIA was induced in female Lewis rats and randomly placed into a LPT groups or sham groups. Experiments were repeated using different LPT protocols varying the frequency and number of LPT treatments. However in each experiment LPT consisted of rhythmically pressing below the rib cage once a second for 30 seconds, while the sham group was held for 30 seconds. Joint inflammation was determined by measuring ankle circumferences and by articular index scoring. Ankles were collected and homogenized to determine changes in synovial cytokine levels by magnetic immunoassays and ELISA. Clustering LPT treatments three-times a day at the peak of joint inflammation had the greatest impact on arthritis. Animals treated with LPT in this manner exhibited significantly reduced ankle edema and inflammation. Additionally, synovial levels of inflammatory cytokines (GRO, IL17, and IL-6) were reduced with LPT. These results indicate that LPT can reduce joint edema and inflammation in a rat model of RA.

Manzamine A (MZA) has differential effects on osteoarthritis (OA) fibroblast expression of MCP-1 and IL-6 (54.26)

MZA is a complex alkaloid compound with anti-inflammatory properties that has recently been synthesized. OA has been characterized to have an inflammatory component involving increased cytokine release by synovial tissue fibroblasts. We hypothesized that MZA treatment of OA fibroblasts could decrease their production of pro-inflammatory cytokines at non-toxic concentrations. OA fibroblasts were isolated with IRB approval, treated with MZA or vehicle, and viability was assessed using multiple methods. OA fibroblast condition media (CM) was collected at various time points after MZA or control treatment, screened by antibody microarrays, and verified by ELISAs. Toxicity studies on OA fibroblasts suggested that concentrations up to 2.5 µM MZA were not toxic using a sensitive flow cytometry kit (results varied in a method-, time-, and concentration-dependent manner). Antibody microarray performed on CM pooled from 5 primary OA fibroblast lines treated with 10 µM MZA for 24 hrs suggested that monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 were two of the most prominent proteins detected, and MZA appeared to decrease MCP-1 production. ELISAs suggested that concentrations of 0.5 µM MZA and higher significantly decreased production of MCP-1 (n=5; p<0.05). In contrast, 1.25 µM MZA appeared to increase IL-6 production, while other concentrations inhibited it. Our data suggest that MZA could alter cytokine production at non-toxic concentrations.

Rheumatoid arthritis synovial tissue fibroblast Mucin 3 expression and function (54.27)

Mucin 3 (MUC3) is elevated in rheumatoid arthritis (RA) synovial tissues (STs). We hypothesized that MUC3 is expressed by RA synovial fibroblasts, that it is cytokine inducible and chemotactic for RA synovial fibroblasts. To test this, RA synovial fibroblast MUC3 expression was determined by immunohistochemistry, flow cytometry and Western blot analysis. Levels of MUC3 from arthritic synovial fluids (SFs) were measured by a novel MUC3 ELISA. RA synovial fibroblast chemotaxis to RA SFs was assessed using a modified Boyden chamber assay. RA ST cells stained for both MUC3 and vimentin indicating that RA synovial fibroblasts express MUC3. Flow cytometry experiments showed that most of the RA synovial fibroblast MUC3 is cytoplasmic. Cytokine stimulation of these cells significantly increased MUC3 production (P<0.05). RA SFs contain on average 8.7μg/ml (n=8) of MUC3. Immunodepletion of MUC3 from RA SFs resulted in significantly reduced RA synovial fibroblast chemotaxis (P<0.05, n=5 RA SFs and n=8 RA synovial fibroblasts). These results show that MUC3 is produced by synovial fibroblasts in RA STs, that MUC3 is inducible by cytokine stimulation and that RA SF induced synovial fibroblast chemotaxis can be inhibited by depleting MUC3. Thus, MUC3 synovial fibroblast production may be induced by the inflammatory milieu of the RA joint and may drive synovial fibroblast chemotaxis within the RA ST potentially aiding pannus formation and cartilage destruction.

The Effects of Manzamine A (MZA) on Synovial Fibroblast Adhesion (173.32)

Isolated from sponges on the ocean floor, MZA has anti-inflammatory properties which might be beneficial in treating rheumatoid arthritis (RA) or osteoarthritis (OA). Preliminary data suggested that MZA causes RA fibroblast-like synoviocytes (FLS) to detach from gelatin. We hypothesized that MZA decreased the adhesive properties of synovial fibroblasts isolated from RA, OA, or normal joints. All fibroblasts were isolated from tissues collected from patients with IRB approval. Photos of cells were taken at various time points (1, 2, 4, 8, 12, and 24 hrs) and counted for adherence after treatment with various concentrations of MZA or vehicle on gelatin, collagen, or laminin substrates. Flow cytometry was used to determine α1 integrin subunit expression on various cell types, since this subunit is important in binding to adhesive substrates. RA FLS on gelatin appeared most sensitive to MZA, in that 1 µM could significantly detach cells in as little as 8 hrs (n=4, p<0.05). RA FLS were more adherent to laminin and most adherent to collagen IV. In contrast, normal or OA fibroblasts on gelatin required incubation with 10 µM MZA for 12 hrs to obtain significant detachment. Flow cytometry did not demonstrate differences in α1 integrin expression between MZA treated cell types (RA FLS, OA fibroblasts, or normals) and controls. We conclude that MZA is exerting both a concentration and time dependent effect on cell adhesion and that α1 integrin may not be involved.

Adult aqueductal stenosis presenting as a thunderclap headache: a case report

Thunderclap headache is well known to be a presenting feature of a variety of causal events. Indeed, a primary form is considered in the International Classification of Headache Disorders-II, but such diagnosis must be made only after exclusion of a possible secondary cause. We report a case of late-onset idiopathic aqueductal stenosis presenting with thunderclap headache, in the absence of abnormal neurological findings or indirect signs of raised intracranial pressure. The patient recovered completely after endoscopic third ventriculostomy. This case indicates primary aqueduct stenosis as a possible, never previously reported, cause of thunderclap headache.

Civilian gunshot wounds to the head with brain stem localization. A case report

The authors present a case of a patient wounded to the head and back by civilian firearm projectiles. The case peculiarity is that only one bullet reached the brain stem level causing significant neurological deficits. The final clinical picture is comparable to the "caudal pontine tegmentum syndrome". The authors describe both the bullet path and the intracranial localization taking into account ballistic details. The problems associated with prognosis, diagnosis, and treatment for gunshot wounds are discussed. In addition, the authors explain the main intracranial lesions and their mechanisms, the role of investigation, and the protocol of medical and surgical treatment. Lastly, a systematic approach for treating these types of gunshot wounds is outlined.

Curved CT reformatted images of head scans

Attempts have been made to overcome the limited visibility of anatomic structures on axial CT by direct multiplanar sections or multiplanar reformatted views. So as not to be restricted by "planar cuts," we have used curved coronal reformatting to investigate some of the cranial structures, whose tortuous anatomy cannot be visualized entirely with standard CT. In fact, we have provided a "flattened" presentation of the optic nerve and chiasma, facial nerve canal, and jugular foramen, showing them in their entire extension. Despite the geometrical deformation produced by this technique, its potential to depict the anatomy of some structures is noteworthy.