CD27(-)CD38(low)CD21(low) B-Cells Are Increased in Axial Spondyloarthritis

B-cells have received little attention in axial spondyloarthritis (axSpA) and for this reason their role in pathogenesis remains unclear. However, there are indications that B-cells may be involved in the disease process. Our objective was to obtain insights into the composition of the peripheral B-cell compartment of axSpA patients compared to healthy donors (HD) and patients with primary Sjögren’s syndrome (pSS), a typical B-cell-associated autoimmune disease. Special emphasis was given to CD27-negative B-cells expressing low levels of CD21 (CD21(low) B-cells), since this subset is implicated in autoimmune diseases with strong involvement of B-cells. Transitional B-cells (CD38(hi)) were excluded from the analysis of the CD27(-)CD21(low) B-cell compartment. This study included 45 axSpA patients, 20 pSS patients and 30 HDs. Intriguingly, compared to HDs the frequency of CD27(-)CD38(low)CD21(low) B-cells was significantly elevated in both axSpA and pSS patients (P<0.0001 for both comparisons). The frequency of CD27(-)CD38(low)CD21(low) B-cells expressing the activation-induced immune markers T-bet and CD11c was decreased in axSpA patients compared to HDs. A higher proportion of CD27(-)CD38(low)CD21(low) B-cells expressed the chemokine receptor CXCR3 in axSpA compared to HDs, suggestive for active involvement of these cells in an inflammatory process. The frequency of CD27(-)CD38(low)CD21(low) B-cells in axSpA patients correlated positively with age and erythrocyte sedimentation rate. Furthermore, axSpA patients with extra-skeletal manifestations (ESM) showed increased frequencies of CD27(-)CD38(low)CD21(low) B-cells compared to patients without ESM. In conclusion, our findings are suggestive of active B-cell involvement in the pathogenesis of axSpA, against prevailing dogma

Phagocytosis is a primary determinant of pulmonary clearance of clinical Klebsiella pneumoniae isolates

INTRODUCTION: METHODS: We screened 19 clinical respiratory RESULTS: The respiratory CONCLUSION: Altogether, these findings show that phagocytosis is a primary determinant of pulmonary clearance of clinica

TMS motor mapping: Comparing the absolute reliability of digital reconstruction methods to the golden standard

Background: Changes in transcranial magnetic stimulation motor map parameters can be used to quantify plasticity in the human motor cortex. The golden standard uses a counting analysis of motor evoked potentials (MEPs) acquired with a predefined grid. Recently, digital reconstruction methods have been proposed, allowing MEPs to be acquired with a faster pseudorandom procedure. However, the reliability of these reconstruction methods has never been compared to the golden standard. Objective: To compare the absolute reliability of the reconstruction methods with the golden standard. Methods: In 21 healthy subjects, both grid and pseudorandom acquisition were performed twice on the first day and once on the second day. The standard error of measurement was calculated for the counting analysis and the digital reconstructions. Results: The standard error of measurement was at least equal using digital reconstructions. Conclusion: Pseudorandom acquisition and digital reconstruction can be used in intervention studies without sacrificing reliability

Cerebellar transcranial direct current stimulation interacts with BDNF Val66Met in motor learning

Background: Cerebellar transcranial direct current stimulation has been reported to enhance motor associative learning and motor adaptation, holding promise for clinical application in patients with movement disorders. However, behavioral benefits from cerebellar tDCS have been inconsistent. Objective: Identifying determinants of treatment success is necessary. BDNF Val66Met is a candidate determinant, because the polymorphism is associated with motor skill learning and BDNF is thought to mediate tDCS effects. Methods: We undertook two cerebellar tDCS studies in subjects genotyped for BDNF Val66Met. Subjects performed an eyeblink conditioning task and received sham, anodal or cathodal tDCS (N = 117, between-subjects design) or a vestibulo-ocular reflex adaptation task and received sham and anodal tDCS (N = 51 subjects, within-subjects design). Performance was quantified as a learning parameter from 0 to 100%. We investigated (1) the distribution of the learning parameter with mixture modeling presented as the mean (M), standard deviation (S) and proportion (P) of the groups, and (2) the role of BDNF Val66Met and cerebellar tDCS using linear regression presented as the regression coefficients (B) and odds ratios (OR) with equally-tailed intervals (ETIs). Results: For the eyeblink conditioning task, we found distinct groups of learners (MLearner = 67.2%; SLearner = 14.7%; PLearner = 61.6%) and non-learners (MNon-learner = 14.2%; SNon-learner = 8.0%; PNon-learner = 38.4%). Carriers of the BDNF Val66Met polymorphism were more likely to be learners (OR = 2.7 [1.2 6.2]). Within the group of learners, anodal tDCS supported eyeblink conditioning in BDNF Val66Met non-carriers (B = 11.9% 95%ETI = [0.8 23.0]%), but not in carriers (B = 1.0% 95%ETI = [-10.2 12.1]%). For the vestibulo-ocular reflex adaptation task, we found no effect of BDNF Val66Met (B = −2.0% 95%ETI = [-8.7 4.7]%) or anodal tDCS in either carriers (B = 3.4% 95%ETI = [-3.2 9.5]%) or non-carriers (B = 0.6% 95%ETI = [-3.4 4.8]%). Finally, we performed additional saccade and visuomotor adaptation experiments (N = 72) to investigate the general role of BDNF Val66Met in cerebellum-dependent learning and found no difference between carriers and non-carriers for both saccade (B = 1.0% 95%ETI = [-8.6 10.6]%) and visuomotor adaptation (B = 2.7% 95%ETI = [-2.5 7.9]%). Conclusions: The specific role for BDNF Val66Met in eyeblink conditioning, but not vestibulo-ocular reflex adaptation, saccade adaptation or visuomotor adaptation could be related to dominance of the role of simple spike suppression of cerebellar Purkinje cells with a high baseline firing frequency in eyeblink conditioning. Susceptibility of non-carriers to anodal tDCS in eyeblink conditioning might be explained by a relatively larger effect of tDCS-induced subthreshold depolarization in this group, which might increase the spontaneous firing frequency up to the level of that of the carriers

Lower respiratory tract myeloid cells harbor SARS-CoV-2 and display an inflammatory phenotype

SARS-CoV-2 pneumonia may induce an aberrant immune response with brisk recruitment of myeloid cells into the airspaces. Although the clinical implications are unclear, others have suggested that infiltrating myeloid cells may contribute to morbidity and mortality during SARS-CoV-2 infection.1–3 However, few reports have characterized myeloid cells from the lower respiratory tract, which appears to be the primary site of viral-induced pathology, during severe SARS-CoV-2 pneumonia

Investigating innate immune responses against pulmonary Klebsiella pneumoniae infection: a role for BATF2

The Gram-negative bacterium Klebsiella pneumoniae (Kp) is a common cause of hospital- acquired bacterial pneumonia, and Kp infections are increasingly resistant to antibiotic treatment, including to carbapenems, which are often used as last-resort antibiotics. A better understanding of the host mechanisms that protect against Kp infection may aid in the development of alternative strategies to combat the threat of multidrug-resistant Kp. Our lab recently identified BATF2 as one of the most highly upregulated genes in LPS- treated human alveolar macrophages. BATF2 has recently emerged as a transcriptional regulator of the innate immune system, but the signaling pathways that induce BATF2 expression in macrophages in response to Gram-negative stimuli are incompletely understood, as is the role of BATF2 in the host response to pulmonary infection with Gram-negative bacteria like Kp. In this dissertation, we show that Kp-induced Batf2 gene expression in macrophages in vitro requires TRIF and type I IFN signaling, but not MyD88 signaling. In addition, using Batf2-/- macrophages and Batf2-/- mice, we show that BATF2 enhances pro-inflammatory cytokine responses in macrophages and contributes to the host defense against pulmonary Kp infection. Prior studies have suggested that evasion of phagocytosis is an important virulence strategy of Kp, but few studies have examined this using clinical isolates. In the current dissertation, we therefore also investigated sensitivity to phagocytic uptake across clinical Kp isolates and show that there is significant heterogeneity in susceptibility to macrophage phagocytosis across respiratory Kp isolates. In addition, we show that pulmonary infection with the phagocytosis-sensitive isolate S17 results in a lower bacterial burden and a reduced inflammatory response compared to infection with the phagocytosis-resistant isolate W42. Importantly, we also show that depletion of alveolar macrophages impaired host defense against the phagocytosis-sensitive S17 isolate, while alveolar macrophage depletion did not significantly affect host defense against the phagocytosis-resistant W42 isolate. Altogether, the findings from this set of experiments show that sensitivity to phagocytosis is an important determinant of pulmonary clearance of clinical respiratory Kp isolates

Cholestasis-associated glucocorticoid overexposure does not increase atherogenesis

Chronic glucocorticoid overexposure predisposes to the development of atherosclerotic cardiovascular disease in humans. Cholestatic liver disease is associated with increased plasma glucocorticoid levels. Here we determined, in a preclinical setting, whether the chronic presence of cholestatic liver disease also induces a concomitant negative impact on atherosclerosis susceptibility. Hereto, regular chow diet-fed atherosclerosis-susceptible hypercholesterolemic apolipoprotein E (APOE) knockout mice were treated with the bile duct toxicant alpha‑naphthylisothiocyanate (ANIT) for 8 weeks. ANIT exposure induced the development of fibrotic cholestatic liver disease as evident from collagen deposits and compensatory bile duct hyperproliferation within the liver and the rise in plasma levels of bilirubin (+60%; P<0.01) and bile acids (10-fold higher; P<0.01). Adrenal weights (+22%; P<0.01) and plasma corticosterone levels (+72%; P<0.01) were increased in ANIT-treated mice. In contrast, atherosclerosis susceptibility was not increased in response to ANIT feeding, despite the concomitant increase in plasma free cholesterol (+30%; P<0.01) and cholesteryl ester (+42%; P<0.001) levels. The ANIT-induced hypercorticosteronemia coincided with marked immunosuppression as judged from the 50% reduction (P<0.001) in circulating lymphocyte numbers. However, hepatic glucocorticoid signaling was not enhanced after ANIT treatment. It thus appears that the immunosuppressive effect of glucocorticoids is uncoupled from their metabolic effect under cholestatic disease conditions. In conclusion, we have shown that cholestatic liver disease-associated endogenous glucocorticoid overexposure does not increase atherosclerosis susceptibility in APOE knockout mice. Our studies provide novel preclinical evidence for the observations that the hypercholesterolemia seen in cholestatic human subjects does not translate into a higher risk for atherosclerotic cardiovascular disease

Endogenous glucocorticoids exacerbate cholestasis-associated liver injury and hypercholesterolemia in mice

Cholestatic liver disease is characterized by a disruption of bile flow, bile acid toxicity, liver injury, and hypercholesterolemia. Relatively high secretion of glucocorticoids by the adrenals has been observed under cholestatic conditions. Here we investigated a contribution of the rise in endogenous glucocorticoids to initial stage cholestasis pathology. Adrenalectomized or sham-operated control C57BL/6 mice were given an oral dose of alpha-naphthylisothiocyanate to induce cholestasis. Adrenalectomy effectively lowered plasma corticosterone levels (18 +/- 5 ng/ml vs 472 +/- 58 ng/ml; P &lt;0.001) and disrupted the metabolic and anti-inflammatory glucocorticoid function. Adrenal removal did not exacerbate the cholestasis extent. In contrast, the cholestasis-associated liver injury was markedly lower in adrenalectomized mice as compared to controls as evidenced by a 84%-93% decrease in liver necrosis and plasma alanine aminotransferase and bile acid levels (P &lt;0.001 for all). Gene expression analysis on livers from adrenalectomized mice suggested the absence of bile acid toxicity-associated farnesoid X receptor signaling in the context of a 44% (P &lt;0.01) and 82% (P &lt;0.001) reduction in sodium/bile acid cotransporter member 1 transcript level as compared to respectively control and non-diseased mice. Adrenalectomy reduced the expression of the cholesterol synthesis gene HMG-CoA reductase by 70% (P &lt;0.05), which translated into a 73% lower plasma total cholesterol level (P &lt;0.05). Treatment of C57BL/6 mice with the glucocorticoid receptor antagonist RU-486 recapitulated the protective effect of adrenalectomy on indices of liver injury and hypercholesterolemia.In conclusion, we have shown that endogenous glucocorticoids exacerbate the liver injury and hypercholesterolemia associated with acute cholestasis in mice. (C) 2016 Elsevier Inc. All rights reserved.</p