OP0100 MOLECULAR PROFILING OF PERIPHERAL IMMUNE CELL SUBSETS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that affects 1% of the world’s population. Several key biological functions are dysregulated in RA, manifesting clinically as pain, fatigue, and synovitis, with articular destruction, organ-based comorbidities, and functional decline. Defining immune dysregulation in the peripheral blood of patients (pts) with RA will help inform future work to assess the extent to which immune homeostasis can be therapeutically achieved for these pts.

Objectives:

To identify baseline molecular characteristics of the peripheral immune system, at the level of individual immune cell subsets, in pts with RA recruited to clinical trials of the oral, selective Janus kinase 1 (JAK1) inhibitor, filgotinib.

Methods:

Peripheral blood mononuclear cells (PBMC) were collected from 324 pts with moderate to severely active RA, who had an inadequate response to methotrexate ([MTX], FINCH-1;NCT02889796; n=109) or who were MTX naïve (FINCH-3;NCT02886728; n=215). PBMC were also collected from 50 demographically matched healthy volunteers (HV). The Immune Profiler platform was used to sort PBMC into 24 immune cell subsets, then quantify their gene expression and chromatin accessibility using RNA-seq and the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq), respectively. Differentially expressed genes (DEGs) and differentially accessible regions (DARs) were identified among immune cell subsets from pts with RA versus HV. Gene set signature scores of Molecular Signatures Database hallmark pathways were calculated using single sample gene set enrichment analysis (ssGSEA) to examine differences in pathway activity between groups.

Results:

A total of 14,500 sequencing datasets were generated from the pt and HV immune cell subsets. Among these, over 26,000 DEGs and 220,000 DARs were identified in RA versus HV (false discovery rate <0.05) across the 24 immune cell subsets. DEGs were identified in all immune cell subsets tested and were most pronounced in natural killer (NK) subsets; most DARs were detected in myeloid and NK subsets. ssGSEA revealed differential pathway signaling in RA versus HV across multiple functions at the immune cell subset level. Myeloid subsets from pts with RA often showed elevated pathway activities versus HV whereas B, T and NK subsets showed a general decrease. In particular, monocyte populations from pts with RA versus HV had elevated pathway activities involved in inflammatory response and interleukin-6/Janus kinase/signal transducer and activator of transcription 3 signaling. The B, T and NK subsets showed a general decrease in tumor necrosis factor-α signaling; conversely, monocyte subsets showed an increase. Prior MTX exposure did not have a notable impact on the detected molecular profile.

Conclusion:

Differences in gene expression, hallmark pathway activity, and chromatin accessibility were identified in RA versus HV at the immune cell subset level. Significant contributions to differences in chromatin accessibility identified in the myeloid and NK cell populations suggest that there are more active regulatory sequences in these cell types that are associated with RA. Further investigations based on these findings may increase understanding of the immune regulatory paradigm in the context of RA.

Acknowledgments:

This study was funded by Gilead Sciences, Inc. Editorial support was provided by Fishawack Communications Inc and funded by Gilead Sciences, Inc.

Disclosure of Interests:

Peter C. Taylor Grant/research support from: Celgene, Eli Lilly and Company, Galapagos, and Gilead, Consultant of: AbbVie, Biogen, Eli Lilly and Company, Fresenius, Galapagos, Gilead, GlaxoSmithKline, Janssen, Nordic Pharma, Pfizer Roche, and UCB, Jinfeng Liu Shareholder of: Gilead Sciences Inc., Roche, Employee of: Gilead Sciences Inc., Luting Zhuo Employee of: Gilead Sciences Inc., Yuan Tian Employee of: Gilead Sciences Inc., Thomas Snyder Employee of: Verily Life Sciences, Charlie Kim Employee of: Verily Life Sciences, Pouya Kheradpour Employee of: Verily Life Sciences, Kat Drake Employee of: Verily Life Sciences, Sam Kim Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., Rachael E. Hawtin Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc.

Dust trajectory sensor: accuracy and data analysis

The Dust Trajectory Sensor (DTS) instrument is developed for the measurement of the velocity vector of cosmic dust particles. The trajectory information is imperative in determining the particles' origin and distinguishing dust particles from different sources. The velocity vector also reveals information on the history of interaction between the charged dust particle and the magnetospheric or interplanetary space environment. The DTS operational principle is based on measuring the induced charge from the dust on an array of wire electrodes. In recent work, the DTS geometry has been optimized [S. Auer, E. Grün, S. Kempf, R. Srama, A. Srowig, Z. Sternovsky, and V Tschernjawski, Rev. Sci. Instrum. 79, 084501 (2008)] and a method of triggering was developed [S. Auer, G. Lawrence, E. Grün, H. Henkel, S. Kempf, R. Srama, and Z. Sternovsky, Nucl. Instrum. Methods Phys. Res. A 622, 74 (2010)]. This article presents the method of analyzing the DTS data and results from a parametric study on the accuracy of the measurements. A laboratory version of the DTS has been constructed and tested with particles in the velocity range of 2-5 km/s using the Heidelberg dust accelerator facility. Both the numerical study and the analyzed experimental data show that the accuracy of the DTS instrument is better than about 1% in velocity and 1° in direction.

[Multifocal motor neuropathies with conduction block: long-term follow-up of ten patients treated with IVIg]

Multifocal motor neuropathy (MMN) with conduction block responds to high-dose i.v. polyvalent immunoglobulins (IVIg) over the short term, but several studies have demonstrated a long-term increase in the degree of axonal degeneration and the number of conduction blocks, factors indicating a poor prognosis. The objective of this study was to evaluate the long-term effect of IVIg on clinical and neurophysiological parameters.

METHODS

We reviewed the records of ten patients who had initially responded well to IVIg and received regular, long-term treatment. The parameters studied were muscular strength, motor function status (modified Rankin scale), as well as the number and progression of conduction blocks and the degree of axonal degeneration. Patients were followed up for a mean of 7.25 years (range, 3.5-12). They were all initially treated with 2 g IgIV/kg in 5 days every 4 weeks for 3 months. Maintenance therapy was administered every 4 weeks with dose adjustment to prevent muscular strength deterioration.

RESULTS

We noted a significant and persistent improvement in muscular strength and in the Rankin motor function score over the long term, with no escape phenomenon. The number of conduction blocks and the degree of axonal degeneration decreased markedly.

CONCLUSION

IVIg treatment remains effective over the long term in MMN. These conclusions differ from those of other authors in earlier studies, but our patients were treated with significantly higher doses of IVIg. These results have important implications for long-term treatment of patients with MMN.

TGF-beta receptor expression and binding in rat mesangial cells: modulation by glucose and cyclic mechanical strain

BACKGROUND

Transforming growth factor-beta (TGF-beta) is a causal factor in experimental glomerulosclerosis, and it mediates the increased extracellular matrix (ECM) accumulation that occurs in cultured mesangial cells (MCs) exposed to high glucose concentrations and cyclic mechanical strain. This change is associated with increased levels of TGF-beta, but may also involve alterations in receptor expression and binding.

METHODS

Rat MCs cultured in media containing either 8 or 35 mM glucose were seeded into culture plates with elastin-coated flexible bottoms. Thereafter, they were subjected to cyclic stretch or static conditions and then examined for 125I-TGF-beta1 binding and expression of TGF-beta receptors at the gene and protein levels.

RESULTS

Kinetic studies showed that MCs bound TGF-beta1 in a time- and concentration-dependent manner, expressing 6800 high-affinity receptors per cell, with an apparent dissociation constant (Kd) of 15.4 pM, while cross-linking analysis identified three TGF-beta receptors (betaR) corresponding to betaRI, betaRII, and betaRIII of 54, 73, and 200 kDa, respectively. Immunocytochemical studies of betaRI and betaRII protein revealed MC expression in a homogeneous, punctate distribution, whereas Northern analysis demonstrated the presence of the corresponding mRNAs. Exposure to cyclic stretching significantly increased (10%) the overall number of TGF-beta receptors, whereas ligands associated with betaRs I, II, and III also increased (25 to 50%). The finding of increased (30 to 40%) betaRI and betaRII transcript levels and immunoreactive protein (163 and 59%, respectively) in the absence of significant changes in the apparent Kd indicated that stretch-induced binding was the result of increased receptor synthesis and expression and not due to a change in binding affinity. In a similar, but more dramatic fashion, exposure to high glucose also elevated (50%) the receptor number, as well as the amount of ligands associated with betaRs I, II, and III (100 to 250%). This same treatment also increased the levels of betaRI and betaRII mRNA (30 to 40%) and the immunoreactive protein (82 and 82%, respectively), without significantly altering the binding affinity of the receptor. A concerted or synergistic effect of both stimuli was not evidenced.

CONCLUSION

These results suggest that the modulation of TGF-beta receptors may be an additional control point in mediating the glucose- and mechanical force-induced increase in ECM deposition by MCs.

Mechanical dysfunction of the left atrium and the left atrial appendage following cardioversion of atrial fibrillation and its relation to total electrical energy used for cardioversion

In 39 patients undergoing electrical cardioversion for atrial fibrillation (AF), we examined the effect of total electrical energy used for cardioversion on postcardioversion peak left atrial (LA) rapid filling velocity (A) and the atrial emptying fraction, and recovery of LA effective mechanical atrial function (defined as peak A velocity > or = 0.50 m/s), as assessed by transthoracic echocardiography. In a subset of 27 patients who underwent pre- and postcardioversion transesophageal echocardiography, we assessed the relation between total electrical energy and LA appendage filling and emptying velocities and spontaneous echo contrast. Patients were randomized to receive an initial shock of 1.5 J/kg based on body weight, or 2.5, 3.5, 5 J/kg, or 360 J, followed sequentially by higher shock intensities until sinus rhythm was achieved. Patients were classified into 4 groups based on quartiles of total energy delivered for cardioversion. Conversion to sinus rhythm was associated with a significant decrease in the LA appendage filling velocities (0.42 +/- 0.20 m/s vs 0.29 +/- 0.14 m/s; p = 0.002) and LA appendage emptying velocities (0.40 +/- 0.22 m/s vs 0.29 +/- 0.18 m/s; p = 0.03), but no change in the incidence of spontaneous echo contrast (61% vs 70%, p = 0.08). The 4 groups of patients did not differ with respect to postcardioversion LA appendage filling velocities, LA appendage emptying velocities, incidence of spontaneous echo contrast, or worsening of spontaneous echo contrast. Similarly, the change in LA appendage filling and emptying velocities associated with cardioversion was not different between the groups. Furthermore, postcardioversion peak A velocity and atrial emptying fraction and recovery of effective mechanical atrial function were similar between the 4 groups. These results suggest that in patients undergoing electrical cardioversion for AF, the total electrical energy used for cardioversion has no effect on the mechanical function of the left atrium or LA appendage following cardioversion.

Sex differences in the adrenal catecholamine response to hypoglycemia in rats

We studied the influence of sex on the adrenal catecholamine response to acute insulin-induced hypoglycemia in Sprague-Dawley rats. Eight male and seven female adult rats were anesthetized with pentobarbital, and a microdialysis probe was placed in the left adrenal. Dialyzed epinephrine and norepinephrine levels were measured by high-performance liquid chromatography during a control period and for 1 hour after insulin administration. The blood glucose level was measured every 15 minutes. The same protocol was applied to 23 adult females at various stages of the estrus cycle. The pattern of blood glucose changes during insulin-induced hypoglycemia was similar in both sexes, but males exhibited a significantly greater increase in epinephrine than females (261% v 52%, P = .001) in the sex-comparison experiment. A similar trend was observed for norepinephrine (73% v 0%, P = .075). The adrenal response in females for both catecholamines was not significantly affected by the estrus cycle phase (P = .989 for epinephrine and P = .424 for norepinephrine). We conclude that sex influences the magnitude of the adrenal catecholamine counterregulatory response to hypoglycemia. Males had a significantly greater increase in epinephrine release than females exposed to the same pattern of hypoglycemia. Female responses to hypoglycemia were not influenced by estrus cyclicity.

Eye tracking dysfunction in schizophrenia: characterization of component eye movement abnormalities, diagnostic specificity, and the role of attention

To characterize oculomotor components and diagnostic specificity of eye tracking abnormalities in schizophrenia, we examined a large consecutively admitted series of psychotic patients and matched controls. The most common abnormality in schizophrenic patients was low gain (slow) pursuit eye movements (47% of cases). Pursuit and saccadic eye movement abnormalities were no more severe in schizophrenic Ss than in those with affective psychoses, except that high rates of catch-up saccades were unique to schizophrenic Ss (17% of cases). These findings indicate that impaired pursuit eye movements are a major cause of eye tracking impairments in schizophrenia, that tracking dysfunctions commonly occur in affective psychoses, and that markedly high rates of catch-up saccades during eye tracking may be specific to schizophrenia.

Eye tracking dysfunction in schizophrenia: characterization of component eye movement abnormalities, diagnostic specificity, and the role of attention

To characterize oculomotor components and diagnostic specificity of eye tracking abnormalities in schizophrenia, we examined a large consecutively admitted series of psychotic patients and matched controls. The most common abnormality in schizophrenic patients was low gain (slow) pursuit eye movements (47% of cases). Pursuit and saccadic eye movement abnormalities were no more severe in schizophrenic Ss than in those with affective psychoses, except that high rates of catch-up saccades were unique to schizophrenic Ss (17% of cases). These findings indicate that impaired pursuit eye movements are a major cause of eye tracking impairments in schizophrenia, that tracking dysfunctions commonly occur in affective psychoses, and that markedly high rates of catch-up saccades during eye tracking may be specific to schizophrenia.

Water excretion by hydra

Hydra were cut so that regenerates consisting only of the central gastric region were formed. This region, which has no natural opening to the environment, is capable of osmoregulation and of removing excess fluid from the gut. The fluid is excreted through a break in the body wall created as a result of a strong contraction when the gut is distended with fluid. A normal hydra, therefore, must remove excess fluid by contracting and expelling it through its mouth.