MicroRNA-320 regulates matrix metalloproteinase-13 expression in chondrogenesis and interleukin-1β-induced chondrocyte responses

OBJECTIVE

Metalloproteinases (MMPs) are key regulators of osteoarthritis (OA) and collagen degradation and have been shown to participate in endochondral ossification. The aim of this study was to determine whether microRNA-320 (miR-320) regulates the expression of MMP-13 in chondrogenesis and inflammation.

EXPERIMENTAL DESIGN

miR-320 expression was assessed in vitro, in the ATDC5 cell model of chondrogenesis and in interleukin-1β (IL-1β)-treated primary mouse chondrocytes (PMCs), and in vivo, in normal and OA human cartilage by in situ hybridization. ATDC5 and PMCs were transfected with miR-320 or its antisense inhibitor (anti-miR-320), respectively. The roles of activated MAP kinases (MAPK) and NF-κB were evaluated by using specific inhibitors. Direct interaction between miR-320 and its putative binding site in the 3'-untranslated region (3'-UTR) of Mmp-13 mRNA was confirmed by the luciferase reporter assay.

RESULTS

miR-320 expression was elevated in chondrogenic and hypertrophic ATDC5, while significantly reduced in OA cartilage compared with normal cartilage. Stimulation with IL-1β led to a significant reduction in miR-320 expression in PMCs. Upregulation of MMP-13 expression was correlated with downregulation of miR-320 expression in both PMCs and ATDC5. Overexpression of miR-320 suppressed the activity of a reporter construct containing the 3'-UTR and inhibited MMP-13 expression in both ATDC5 and IL-1β-treated PMCs, while treatment with anti-miR-320 enhanced MMP-13 expression. NF-κB and MAPK activation downregulated miR-320 expression.

CONCLUSION

Cartilage development and homeostasis are influenced by miR-320, which directly targets MMP-13 and regulates chondrogenesis and the IL-1β-stimulated catabolic effect in mouse chondrocytes.

Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro

Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have synergistic bactericidal effects with antibiotics in vitro. To do this, we used a clinically isolated strain of Staphylococcus aureus 17546 (t037) for biofilm formation. Virulence factors were detected following treatment with baicalein, and the molecular mechanism of its antibiofilm activity was studied. Plate counting, crystal violet staining, and fluorescence microscopy revealed that 32 μg/mL and 64 μg/mL baicalein clearly inhibited 3- and 7-day biofilm formation in vitro. Moreover, colony forming unit count, confocal laser scanning microscopy, and scanning electron microscopy showed that vancomycin (VCM) and baicalein generally enhanced destruction of biofilms, while VCM alone did not. Western blotting and real-time quantitative polymerase chain reaction analyses (RTQ-PCR) confirmed that baicalein treatment reduced staphylococcal enterotoxin A (SEA) and α-hemolysin (hla) levels. Most strikingly, real-time qualitative polymerase chain reaction data demonstrated that 32 μg/mL and 64 μg/mL baicalein downregulated the quorum-sensing system regulators agrA, RNAIII, and sarA, and gene expression of ica, but 16 μg/mL baicalein had no effect. In summary, baicalein inhibited Staphylococcus aureus biofilm formation, destroyed biofilms, increased the permeability of vancomycin, reduced the production of staphylococcal enterotoxin A and α-hemolysin, and inhibited the quorum sensing system. These results support baicalein as a novel drug candidate and an effective treatment strategy for Staphylococcus aureus biofilm-associated infections.

Abstract P5-01-06: 18F-radiolabeled PARP-1 inhibitor uptake as a marker of PARP-1 activity in breast cancer

Objectives: The nuclear enzyme PARP-1 plays a central role in sensing DNA damage and facilitating repair. Tumors with BRCA1/2 mutations are highly dependent on PARP-1 as an alternative mechanism for DNA repair, and PARP inhibitors generate synthetic lethality in tumors with BRCA mutations, resulting in cell cycle arrest and apoptosis. Zhou et al. recently synthesized an 18F-labeled PARP-1 inhibitor (18F-FluorThanatrace) for PET, and demonstrated high specific tracer uptake in a xenograft model of breast cancer (Zhou, Bioorg Med Chem, 22:1700, 2014). The current study seeks to quantify the relationship between 18F-FluorThanatrace binding (both in vitro and on PET imaging of human tumor xenografts) and the level of constitutively active PARP-1, using multiple human breast cancer cell lines, including a BRCA1 defective line.

Methods: BRCA1 defective HCC1937, triple negative MDA-MB-231, and luminal A MCF-7 human breast cancer lines were assessed for constitutive PARP-1 activity via a chemiluminescent ELISA assay for PAR and by Western blot. The same cell lines were incubated with 18F-FluorThanatrace over various time increments, and tracer uptake was assayed via a gamma counter. Specificity of tracer binding was verified via co-incubation with competitive inhibitor Olaparib, and specific tracer uptake was calculated as the difference between uptake with and without Olaparib. Specific tracer uptake was compared to levels of constitutive PARP-1 activity in all cell lines. In addition, HCC1937 and MDA-MB-231 xenograft tumor models were imaged via 18F-FluorThanatrace-PET/CT, and PET uptake was correlated with PARP-1 activity.

Results: BRCA1-defective HCC1937 had higher constitutive PARP-1 activity than cell lines with intact BRCA1. In vitro levels of 18F-FluorThanatrace uptake correlated with constitutive PARP-1 activity across cell lines. In addition, 18F-FluorThanatrace measured by PET in xenograft breast cancer tumor models correlated with constitutive PARP-1 activity.

Conclusions: Tumor uptake of 18F-FluorThanatrace, both in vitro and on PET imaging of xenograft tumor models, quantitatively reflects differences in PARP-1 activity across different breast cancer cell lines, including BRCA1 defective. This motivates further studies of 18F-FluorThanatrace as an in vivo measure of PARP-1 activity and possibly as a predictive marker for PARP-1 therapy in patients, including those with BRCA1/2 mutations.

Citation Format: Edmonds CE, Lieberman BP, Xu K, Zeng C, Makvandi M, Li S, Hou C, Lee H, Greenberg RA, Mankoff DA, Mach RH. 18F-radiolabeled PARP-1 inhibitor uptake as a marker of PARP-1 activity in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-01-06.

Plasma soluble Tim-3 emerges as an inhibitor in sepsis: sepsis contrary to membrane Tim-3 on monocytes

Immune dysfunction is the main characteristic of sepsis. T cell Ig and mucin domain protein 3 (Tim-3) on the monocytes has been reported to promote immune homeostasis during sepsis, but the influences of plasm soluble Tim-3 (sTim-3) on the immune system during sepsis remain unknown. Here, 100 patients with different severities of sepsis (40 sepsis, 42 severe sepsis, and 18 septic shock) were enrolled in this study. The Tim-3 and human leukocyte antigen-DR (HLA-DR) on the circulating monocytes were detected using flow cytometry. Plasma sTim-3 was detected by enzyme-linked immunosorbent assay. Inflammatory factors and two kinds of A disintegrin and metalloprotease (ADAM) - ADAM10 and ADAM17 were assessed. The Tim-3 and HLA-DR on the monocytes decreased with increasing sepsis severity. The sTim-3 was reduced in the sepsis and severe sepsis patients but was elevated in the septic shock patients who exhibited significant immunosuppression as predicted by HLA-DR. sTim-3 levels were negatively correlated with IL-12 and TNF-α. ADAM10 and ADAM17, sheddases of Tim-3, exhibited trends toward elevations in the septic shock group. In conclusion, sTim-3 was involved in the development of sepsis. The homeostasis-promoting role of the Tim-3 on the monocytes was disrupted, while the inhibitory role of sTim-3 emerged during sepsis-induced immunosuppression.

HMGB1 binding to receptor for advanced glycation end products enhances inflammatory responses of human bronchial epithelial cells by activating p38 MAPK and ERK1/2

The proinflammatory factor high mobility group box protein 1 (HMGB1) has been implicated as an important mediator of many chronic inflammatory diseases, including asthma. Human bronchial epithelial cells (HBECs) play a central role in the pathogenesis of asthma. However, the effects of HMGB1 on HBECs and the underlying mechanisms remain unknown. Here, we investigated receptor expression and proinflammatory cytokine production by primary cultures of HBECs stimulated by HMGB1. We then examined the effects of specific receptor blockade and inhibition of p38 MAPK, ERK1/2, or PI3-K on HMGB1-induced expression of proinflammatory cytokines. HMGB1 increased the expression and secretion of TNF-α, TSLP, MMP-9, and VEGF in a dose- and time-dependent manner. HMGB1 also induced elevated expression of RAGE protein. Secretion of TNF-α, VEGF, MMP-9, and TSLP was significantly decreased by RAGE blockade and p38 MAPK pathway inhibition, while a less pronounced effect was mediated by ERK1/2 inhibition. These observations suggest that HMGB1 binds RAGE and promotes activities of p38 MAPK and ERK1/2 pathways in HBECs. This then enhances the expression of TNF-α, VEGF, MMP-9, and TSLP, which are the important inflammatory factors in asthma. These results demonstrate that HMGB1 enhances the inflammatory responses of HBECs, which are involved in the modulation of inflammatory processes in asthma.

Blockade of the T cell immunoglobulin and mucin domain protein 3 pathway exacerbates sepsis-induced immune deviation and immunosuppression

Sepsis is a life-threatening condition, but the pathophysiological basis and biomarkers for the monitoring of sepsis and as targets for therapy remain to be determined. We have shown previously that T cell immunoglobulin and mucin domain protein 3 (Tim-3), a negative immune regulator, is involved in the physiopathology of sepsis, but the underlying mechanisms remain unclear. In the present study, we showed that Tim-3 signalling modulated the response patterns of both macrophages and T helper cells in sepsis. Blockade of the Tim-3 pathway exacerbated sepsis-induced proinflammatory macrophage responses and lymphocyte apoptosis during the early phase of sepsis, and enhanced the shift to anti-inflammatory responses for both macrophages and T helper cells during the late phase of sepsis. Tim-3 signalling was found to regulate CD80 and CD86 expression on macrophages both in vivo and in vitro. Co-culture of T cells with Tim-3 knock-down macrophages led to a biased T helper type 2 (Th2) response, partially explaining how Tim-3 signalling shapes inflammation patterns in vivo. Further studies on this pathway might shed new light on the pathogenesis of sepsis and suggest new approaches for intervention.

Abstract B48: Preclinical development of meta-[211At] astatobenzylguanidine ([211At] MABG) targeted radiotherapy for neuroblastoma

Background: Neuroblastoma (NB) is a radiosensitive malignancy accounting for 10% of childhood cancer mortality. NB cells frequently express the norepinephrine transporter (NET) providing a specific mechanism for uptake of NET-ligands. Meta-[131I]iodobenzylguanidine ([131I]MIBG) is a NET-ligand radiotherapeutic that shows single-agent response rates in refractory NB of 40-50%. However, due to the long path lengths of 131 I beta (β)-emission, and low biological effectiveness compared to alpha (α)-emitting radionuclides, [131I]MIBG is generally not curative, perhaps due to non-targeting of isolated circulating tumor cells. Here we report our efforts to optimize NET-targeted radiotherapy by developing relevant preclinical models of refractory NB for α-particle therapeutic [211At] MABG therapy.

Methods: We first determined NET (SLC6A2) mRNA and protein expression in 35 human NB cell lines using quantitative RT-PCR and western blotting. We then chose 5 lines with absent to intermediate levels of native NET expression (NB1691, SKNSH, IMR5, NLF and SKNBE2) for dual forced overexpression of human NET and luciferase cDNAs. We used [125I]MIBG for cell-based uptake assays in all isogenic pairs and biodistribution experiments in athymic mice bearing three separate NET-transduced xenografts (N=5 per cell line). These cell lines were also treated with [131I]MIBG and/or external beam radiation (XRT) followed by multi-log cytotoxicity assays. Therapeutic trials of [131I]MIBG (25 mCi/kg) in NB1691 subcutaneous xenograft and metastatic mouse models were also conducted. In parallel, [211At] MABG was synthesized by: (i) cyclotron-production of 211 At via 209 Bi(α,2n)211At reaction (ii) distillation of 211 At from the target, and (iii) solid phase no-carrier-added synthesis of [211At] MABG by radioastato-destannylation. [211At] MABG uptake studies were performed in isogenic NB cell lines.

Results: Unlike primary human NBs, NET expression was low in the majority of 35 cell-lines studied (median normalized expression value = 0.145; range 0.000-1.005), but all transduced lines showed significant overexpression (0.860-1.107) comparable to human primary tumors. Transduced lines showed 4-10 fold higher uptake of [125I]MIBG than non-transduced isogenic parental cell lines in vitro, and demonstrated significant tumor-specific uptake and retention in vivo with tumor-muscle ratios ranging from 13.80 to 29.48. In vitro cytotoxicity experiments using [131I]MIBG showed NET-expressing cell lines to be more susceptible to treatment compared to non-NET expressing pairs (IC50 of 2.937nCi vs. 15.99 nCi). Treatment of mice bearing NB1691-NET xenografts with [131I]MIBG showed tumor growth delay (p=0.0065), but no significant impact on survival, likely due to de novo radioresistance (1200 cGy of XRT had no impact on NB1691 proliferation; IMR-05 showed 97% decreased cell viability). Lastly, we successfully synthesized [211At] MABG, with radiochemical yields of ∼20% and showed NET specific uptake of [211At] MABG into 1691 NET transfected cells.

Conclusions: Development of targeted radiotherapy for neuroblastoma has been limited by the lack of preclinical models and alternative therapeutics. Our development of multiple isogenic pairs with varying NET expression, documentation of de novo radiation sensitivity, and the production of [211At] MABG, will allow for rapid assessment of targeted radiotherapeutic strategies (including combination approaches) to support clinical development of alpha-particle therapeutics in a childhood cancer.

Citation Format: V Batra, AM Chacko, M Gagliardi, C Hou, J L. Mikitsh, R H. Freifelder, A Kachur, B C. LeGeyt, A Schmitz, L Toto, G Vaidyanathan, M R. Zalutsky, K K. Matthay, W A. Weiss, W C. Gustafson, D Pryma, J M. Maris. Preclinical development of meta-[211At] astatobenzylguanidine ([211At] MABG) targeted radiotherapy for neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B48.

The effects and underlying mechanism of excessive iodide on excessive fluoride-induced thyroid cytotoxicity

In many regions, excessive fluoride and excessive iodide coexist in groundwater, which may lead to biphasic hazards to human thyroid. To explore fluoride-induced thyroid cytotoxicity and the mechanism underlying the effects of excessive iodide on fluoride-induced cytotoxicity, a thyroid cell line (Nthy-ori 3-1) was exposed to excessive fluoride and/or excessive iodide. Cell viability, lactate dehydrogenase (LDH) leakage, reactive oxygen species (ROS) formation, apoptosis, and the expression levels of inositol-requiring enzyme 1 (IRE1) pathway-related molecules were detected. Fluoride and/or iodide decreased cell viability and increased LDH leakage and apoptosis. ROS, the expression levels of glucose-regulated protein 78 (GRP78), IRE1, C/EBP homologous protein (CHOP), and spliced X-box-binding protein-1 (sXBP-1) were enhanced by fluoride or the combination of the two elements. Collectively, excessive fluoride and excessive iodide have detrimental influences on human thyroid cells. Furthermore, an antagonistic interaction between fluoride and excessive iodide exists, and cytotoxicity may be related to IRE1 pathway-induced apoptosis.

The role of the IRE1 pathway in excessive iodide- and/or fluoride-induced apoptosis in Nthy-ori 3-1 cells in vitro

Excessive iodide and fluoride coexist in the groundwater in many regions, causing a potential risk to the human thyroid. To investigate the mechanism of iodide- and fluoride-induced thyroid cytotoxicity, human thyroid follicular epithelial cells (Nthy-ori 3-1) were treated with different concentrations of potassium iodide (KI), with or without sodium fluoride (NaF). Cell morphology, viability, lactate dehydrogenase (LDH) leakage, apoptosis, and expression of inositol-requiring enzyme 1 (IRE1) pathway-related molecules were assessed. Results showed 50 mM of KI, 1 mM of NaF, and 50 mM of KI +1 mM of NaF changed cellular morphology, decreased viability, and increased LDH leakage and apoptosis. Elevated expression of binding protein (BiP), IRE1, and C/EBP homologous protein (CHOP) mRNA and protein, as well as spliced X-box-binding protein-1 (sXBP-1) mRNA, were observed in the 1 mM NaF and 50 mM KI +1 mM NaF groups. Collectively, excessive iodide and/or fluoride is cytotoxic to the human thyroid. Although these data do not manifest iodide could induce the IRE1 pathway, the cytotoxicity followed by exposure to fluoride alone or in combination with iodide may be related to IRE1 pathway-induced apoptosis. Furthermore, exposure to the combination of excessive iodide and fluoride may cause interactive effects on thyroid cytotoxicity.

Influence of different urination methods on the urinary systems of patients with spinal cord injury

OBJECTIVE

This study evaluated the influence of different urination methods on the urinary systems of patients with spinal cord injury.

METHODS

Patients with spinal cord injury were grouped according to their usual voiding method: clean intermittent catheterization (CIC); Credé manoeuvre/reflex voiding; indwelling catheterization; normal voiding. Urinary tract infections (UTIs) were monitored and type B-ultra-sonography (B-USG) scans, renal function tests and urodynamic studies were performed in all patients over a 2-year period.

RESULTS

Compared with the normal voiding group (n = 14), incidence rates of UTIs were significantly different in the Credé manoeuvre/reflex voiding (n = 26) and indwelling catheterization (n = 12) groups but not in the CIC group (n = 15). All intervention groups had a significantly higher rate of positive findings on B-USG scan and a significantly increased residual urine volume, compared with the normal voiding group. In addition, residual urine volume was significantly lower in the CIC group compared with the Credé manoeuvre/reflex voiding and indwelling catheterization groups.

CONCLUSION

CIC was shown to be the optimal method for assisted bladder voiding after spinal cord injury.

Genetic manipulation of sex ratio for the large-scale breeding of YY super-male and XY all-male yellow catfish (Pelteobagrus fulvidraco (Richardson))

Yellow catfish has become one of the most important freshwater aquaculture species in China. The mono-sex male yellow catfish has important application value in aquaculture because the male grows generally faster than the sibling females under the same conditions. This study has screened YY super-male and YY physiological female yellow catfish by sex reversal, gynogenesis, and progeny testing, which can help to achieve the large-scale production of YY super-male and XY all-male. From 2008 to 2010, about 123,000 YY super-male were produced, and about 81 million XY all-male fry were produced with 100% male rate by random sampling. Therefore, these results indicate that YY super-male and YY physiological female yellow catfish can be viable and fertile. We conclude that the mono-sex breeding technique by YY super-male yellow catfish is stable and reliable, which has great potential for application in yellow catfish aquaculture.

Unilateral lesion of the nigrostriatal pathway decreases the response of GABA interneurons in the dorsal raphe nucleus to 5-HT(1A) receptor stimulation in the rat

This study examined the firing rate and pattern of electrophysiologically and chemically identified GABA interneurons in the dorsal raphe nucleus (DRN), and role of 5-HT(1A) receptor agonist 8-OH-DPAT and the medial prefrontal cortex (mPFC) in the firing activity in rats with 6-hydroxydopamine lesions of the substantia nigra pars compacta (SNc). The interneurons in rats with lesions of the SNc showed a more burst-firing, while having no change in the firing rate; the mPFC and combined mPFC and SNc lesions in rats decreased the firing rate of the interneurons and firing pattern shifted towards a more burst-firing compared to rats with sham lesions of the SNc, respectively. In rats with sham lesions of the SNc, administration of 8-OH-DPAT (1-243 μg/kg, i.v.) produced excitatory-inhibitory, excitatory and inhibitory effects in the firing rate of individual interneurons. However, when these effects were averaged over the group, 8-OH-DPAT had no significant effect on firing rate. In rats with lesions of the SNc, mPFC and the paired lesions, 8-OH-DPAT, at the same doses, inhibited all interneurons tested, respectively. Cumulative doses producing inhibition in rats with the paired lesions were higher than that of rats with lesions of the mPFC. In contrast to rats with sham lesions of the SNc, SNc lesion reduced expression of 5-HT(1A) receptor on parvalbumin positive neurons in the DRN, a subpopulation of GABA interneurons. Our results indicate that the SNc and mPFC regulate the firing activity of GABA interneurons in the DRN. Furthermore, response of likely GABA interneurons to systemic administration of 8-OH-DPAT is altered by lesion of the SNc and mPFC.

[Hydrogen peroxide induces high mobility group box 1 release in human bronchial epithelial cells]

OBJECTIVE

To investigate the effect of hydrogen dioxide (H(2)O(2)) on the release and translocation of high mobility group box 1 release (HMGB1) from normal human bronchiolar epithelial cells (HBE).

METHODS

MTT assay was used to assess the viability of HBE135-E6E7 cells exposed to different concentrations of H(2)O(2). The expression and location of HMGB1 in the cytoplasm, nuclei and culture medium of the exposed cells were determined using Western blotting and immunofluorescence assay.

RESULTS

Exposure to 125 µmmol/L H(2)O(2) did not obviously affect the cell viability. At the concentration of 250 µmmol/L, H(2)O(2) significantly decreased the cell viability (P<0.05), but significant cell death occurred only after exposure to 400 µmmol/L H(2)O(2) (P=0.000). Compared with the control cells, the cells exposed to 12.5, 125 and 250 µmmol/L H(2)O(2) for 24 h showed significantly increased levels of HMGB1 in the culture medium (P<0.05), and exposure to 125 µmmol/L H(2)O(2) for 12 and 24 h also caused significantly increased HMGB1 level (P<0.05). Exposure to 125 µmmol/L H(2)O(2) for 24 h significantly increased HMGB1 expression in the cytoplasm but decreased its expression in the nucleus. HMGB1 translocation from the nuclei to the cytoplasm and to the plasmalemma occurred after 125 µmmol/L H(2)O(2) exposure for 12 h and 24 h, respectively.

CONCLUSION

H(2)O(2) can induce HMGB1 translocation and release in human bronchial epithelial cells, suggesting the involvement of HMGB1 in airway oxidative stress in chronic inflammatory diseases such as asthma and COPD.