POS0314 IDENTIFICATION OF CIRCULATING microRNA SIGNATURES IN PATIENTS WITH PSORIASIS WITH SUBCLINICAL JOINT DISEASE AND PATIENTS WITH PSORIATIC ARTHRITIS

Background

MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression. Specific miRNA signatures have been identified in numerous diseases and may serve as potential biomarkers or new drug targets. Whether certain miRNA signatures are associated with psoriatic joint disease is currently unknown.

Objectives

To search for circulating miRNA signatures in psoriasis patients with subclinical joint disease and in patients with psoriatic arthritis (PsA).

Methods

Analyses of serum miRNA were done in three groups: (1) PsA patients fulfilling CASPAR criteria (PsA), (2) healthy controls without past or present signs of musculoskeletal disease (HC) and (3) psoriasis patients with musculoskeletal pain but no signs of clinical PsA (PsO). PsO and PsA patients received a hand MRI, which was scored according to PsAMRIS method. miRNA analysis of serum samples was performed stepwise using RT-qPCR (TAmiRNA Vienna). In the discovery phase 192 miRNA assays were analyzed in 48 samples (N=16 each group). In the validation phase 17 miRNAs (Table 1) were selected and analyzed in 94 samples (N=35 PsA, N=24 PsO, N=35 HC) based on results of discovery phase and previous reports in literature. Results presented as mean±SD/median (IQR), p-values are adjusted for multiple testing.

Table 1.miRNAsPsA vs HCPsO vs HCPsA vs PsODiscovery PhaseValidation PhaseDiscovery PhaseValidation PhaseDiscovery PhaseValidation Phasep-adj.p-adj.p-adj.p-adj.p-adj.p-adj.miR-93-5p0.0001<0.0010.0080.0050.0390.947miR-29b-3p0.0001<0.00010.0040.00020.1910.522miR-19b-3p0.0070.7080.00020.0200.1380.147miR-320d0.0010.619<0.00010.1350.9410.247miR-144-5p0.0030.0060.00010.1690.3500.444miR-188-5p0.0140.9900.9750.6470.0530.839let-7b-5p0.0250.00030.8890.0260.00030.472miR-92a-3p0.0430.0010.0050.773<0.00010.0005miR-324-3p0.1381.0000.2570.3920.8140.518miR-126-3p0.0140.1690.0130.5980.9220.654miR-223-3p0.1690.8720.6170.7460.5191.000miR-130a-3p0.0390.0350.5560.0090.0060.724miR-140-3p0.3500.0530.0020.0060.1180.683miR-155-5p0.1590.9950.1690.5490.9220.604miR-21-5p0.2970.9900.0030.1160.080.014miR-146a-5p0.7060.0040.8360.0380.9050.941miR-122-5p0.9600.7340.6950.7990.9050.444

Results

51 PsA patients (age: 51.3±11.4 years; 56.9% females), 40 PsO patients (51.4±11.0; 37.5%) and 50 HC (51.0±10.5; 52.9%) were assessed. Duration of psoriasis was 12(25) years in PsA and 15(22.8) years in PsO. Duration of joint disease in PsA was 1.0(4.8) year. 51% of PsA and 5% of PsO patients were on biological disease modifying drugs (bDMARDs), 49% vs. 10% on conventional DMARDs. The most frequent findings in the MRI were erosions (PsA 59.6%; PsO 40%) and synovitis (PsA 48.9%; PsO 42.5%). PsA patients had higher number of tenosynovitis compared to PsO (p=0.04). In discovery phase 51 miRNAs in PsO and 64 miRNAs in PsA were down- or upregulated compared to HC, with an overlap of 33 miRNAs changed in PsA and PsO (p<0.05). Results of the selected 17 miRNAs are presented in Table 1. The top candidates to differentiate PsA and HC were miR-29b-3p (AUC=0.87), miR-93-5p (AUC=0.83) and let-7b-5p (AUC=0.79). For differentiating PsO and HC, they were miR-29b-3p (AUC=0.82), miR-140-3p (AUC=0.81) and miR-19b-3p (AUC=0.80) and for PsO vs. PsA miR-92a-3p (AUC=0.87), let-7b-5p (AUC=0.72) and miR-21-5p (AUC=0.70). miR-93-5p was lower in patients with erosions (p=0.01). miR-92a-3p, let-7b-5p and miR-21-5p were lower in patients with tenosynovitis, bone proliferations or erosions.

Conclusion

PsA and PsO patients show miRNA signatures different from HC. Top candidate miRNAs differentially regulated in PsA and PsO have been previously reported in alteration of bone metabolism and osteoarthritis indicating the intimate association of psoriatic inflammation with bone and cartilage changes.

References

[1]Faustini F et al. Ann Rheum Dis 2016 Dec;75(12):2068-2074

[2]Hackl, M et al. Molecular and Cellular Endocrinology Elsevier Ireland Ltd 432, pp 83–95

[3]Feichtinger X et al. Sci Rep 2018 Mar 20;8(1):4867

Disclosure of Interests

None declared

Diagnostic Performance of a Panel of miRNAs (OsteomiR) for Osteoporosis in a Cohort of Postmenopausal Women

A specific signature of 19 circulating miRNAs (osteomiRs) has been reported to be associated with fragility fractures due to postmenopausal osteoporosis. However, it is unknown whether osteoporotic fractures or low BMD phenotypes are independently contributing to changes in osteomiR serum levels. The first aim was to characterize the abundance, sensitivity to hemolysis, and correlation of osteomiR serum levels, the second objective to evaluate the diagnostic accuracy of osteomiRs for osteoporosis according to the WHO criteria and on basis of major osteoporotic fracture history. Fifty postmenopausal women with osteoporosis (with or without fragility fracture) and 50 non-osteoporotic women were included in this cross-sectional study. The diagnostic performance of osteomiRs for osteoporosis based on the WHO definition or fracture history was evaluated using multiple logistic regression and receiver-operator curve (AUC) analysis. The osteomiR® signature is composed of four clusters of miRNAs providing good performance for the diagnosis of osteoporosis in postmenopausal women defined by WHO criteria (AUC = 0.830) and based on history of major osteoporotic fractures (AUC = 0.834). The classification performance for the WHO criteria and for fracture risk is driven by miR-375 and miR-203a, respectively. OsteomiRs, a signature of 19 emerging miRNA bone biomarkers, are measurable in human serum samples. They constitute a panel of independent bone and muscle biomarkers, which in combination could serve as diagnostic biomarkers for osteoporosis in postmenopausal women.

A novel flow-based assay reveals discrepancies in ADAMTS-13 inhibitor assessment as compared with a conventional clinical static assay

BACKGROUND

Several static Bethesda-type assays are routinely used to determine ADAMTS-13-neutralizing autoantibodies in acquired thrombotic thrombocytopenic purpura (TTP), but the inhibitory activity of these antibodies has not been thoroughly evaluated under the more physiologic condition of flow.

OBJECTIVES

We investigated whether ADAMTS-13 inhibitor assessment with the FRETS-VWF73 assay is predictive for evaluation under flow.

METHODS

Anti-ADAMTS-13 autoantibodies were purified from patients with acquired TTP by chromatography involving an ADAMTS-13 affinity matrix and/or protein G. ADAMTS-13 activity was measured with the FRETS-VWF73 assay and a novel flow assay determining the ADAMTS-13-mediated decrease in platelet aggregate surface coverage, caused by perfusion of a suspension containing platelets, erythrocytes and von Willebrand factor (VWF) over a surface coated with extracellular matrix components. The neutralizing activities of ADAMTS-13 inhibitors were compared under static conditions and under flow by use of the two assays.

RESULTS

The suitability of the flow-based ADAMTS-13 activity assay for quantification of ADAMTS-13 inhibitors could be demonstrated by reversibility of the ADAMTS-13-dependent decrease in surface coverage upon addition of goat ADAMTS-13 antiserum. Testing the neutralizing activity of purified autoantibodies from six patients in the flow assay according to their FRETS-VWF73-based inhibitor titers gave rise to vastly different inhibitory effects, indicating a discrepancy in inhibitor assessment between static and flow conditions.

CONCLUSIONS

Anti-ADAMTS-13 autoantibodies may show inhibitory properties in vivo that are not consistent with the ADAMTS-13 inhibitor levels determined in routine static assays, possibly because certain epitopes are selectively exposed under shear. Consequently, the course of disease and treatment efficacy may vary among TTP patients, despite common inhibitor titers.

Recombinant ADAMTS13 normalizes von Willebrand factor-cleaving activity in plasma of acquired TTP patients by overriding inhibitory antibodies

BACKGROUND

Severe deficiency of the von Willebrand factor (VWF)-cleaving protease ADAMTS13 as observed in acquired thrombotic thrombocytopenic purpura (TTP) is caused by inhibitory and non-inhibitory autoantibodies directed against the protease. Current treatment with plasma exchange is considered to remove circulating antibodies and to concurrently replenish the deficient enzyme.

OBJECTIVES

To explore the use of recombinant ADAMTS13 (rADAMTS13) as a potential therapeutic agent in acquired TTP, we investigated its efficacy in normalizing VWF-cleaving activity in the presence of ADAMTS13 inhibitors.

METHODS

Thirty-six plasma samples from TTP patients were adjusted to predefined inhibitor titers, and recovery of ADAMTS13 activity was analyzed following supplementation with rADAMTS13.

RESULTS

We showed a linear relation between the inhibitor titer measured and effective rADAMTS13 concentration necessary for reconstitution of VWF-cleaving activity in the presence of neutralizing autoantibodies.

CONCLUSIONS

Our results support the further investigation of the potential therapeutic applicability of rADAMTS13 as an adjunctive therapy in acquired TTP.