We investigated the relationships among M1 monocytes, M2 monocytes, osteoclast (OC) differentiation ability, and clinical characteristics in patients with rheumatoid arthritis (RA).
Peripheral blood ...mononuclear cells (PBMCs) were isolated from RA patients and healthy donors, and we then investigated the number of M1 monocytes or M2 monocytes by fluorescence-activated cell sorting. We also obtained and cultured CD14-positive cells from PBMCs from RA patients and healthy donors to investigate OC differentiation
.
Forty RA patients and 20 healthy donors were included. Twenty-two patients (55%) were anticitrullinated protein antibody (ACPA) positive. The median M1/M2 ratio was 0.59 (0.31-1.11, interquartile range). There were no significant differences between the RA patients and healthy donors. There was a positive correlation between the M1/M2 ratio and the differentiated OC number
in RA patients (ρ = 0.81,
< 0.001). The ACPA-positive patients had significantly higher M1/M2 ratios
(
= 0.028) and significantly greater numbers of OCs
(
= 0.005) than the ACPA-negative patients. Multivariable regression analysis revealed that the M1/M2 ratio was the sole significant contribution factor to
osteoclastogenesis. RA patients with M1/M2 ratios >1 (having relatively more M1 monocytes) had higher C-reactive protein and erythrocyte sedimentation rates than RA patients with M1/M2 ratios ≤1. M1-dominant monocytes
produced higher concentrations of interleukin-6 upon stimulation with lipopolysaccharide than M2 monocytes.
M1/M2 monocytes imbalance strongly contributes to osteoclastogenesis of RA patients. Our findings cast M1 and M2 monocyte subsets in a new light as a new target of treatments for RA to prevent progression of osteoclastic bone destruction.
Neutrophil extracellular trap formation (NETosis) and the NLR family pyrin domain containing 3 (NLRP3) inflammasome assembly are associated with a similar spectrum of human disorders. While NETosis ...is known to be regulated by peptidylarginine deiminase 4 (PAD4), the role of the NLRP3 inflammasome in NETosis was not addressed. Here, we establish that under sterile conditions the cannonical NLRP3 inflammasome participates in NETosis. We show apoptosis-associated speck-like protein containing a CARD (ASC) speck assembly and caspase-1 cleavage in stimulated mouse neutrophils without LPS priming. PAD4 was needed for optimal NLRP3 inflammasome assembly by regulating NLRP3 and ASC protein levels post-transcriptionally. Genetic ablation of NLRP3 signaling resulted in impaired NET formation, because NLRP3 supported both nuclear envelope and plasma membrane rupture. Pharmacological inhibition of NLRP3 in either mouse or human neutrophils also diminished NETosis. Finally, NLRP3 deficiency resulted in a lower density of NETs in thrombi produced by a stenosis-induced mouse model of deep vein thrombosis. Altogether, our results indicate a PAD4-dependent formation of the NLRP3 inflammasome in neutrophils and implicate NLRP3 in NETosis under noninfectious conditions
in vitro
and
in vivo
.
NLR family pyrin domain containing 3 (NLRP3) inflammasome mediates caspase-1-dependent processing of inflammatory cytokines such as IL-1β, an essential endothelial activator, and contributes to the ...pathology of inflammatory diseases. To evaluate the role of NLRP3 in neutrophils in endothelial activation, which is still elusive, we used the thioglycollate-induced peritonitis model characterized by an early neutrophil influx, on Nlrp3
and Nlrp3
mice. Nlrp3
mice recruited fewer neutrophils than Nlrp3
into the peritoneum and showed lower IL-1β in peritoneal lavage fluid. The higher production of IL-1β in Nlrp3
was neutrophil-dependent as neutrophil depletion prevented the IL-1β production. The Nlrp3
neutrophils collected from the peritoneal fluid formed significantly more filaments (specks) than Nlrp3
neutrophils of ASC (apoptosis-associated speck-like protein containing a caspase activating and recruitment domain), a readout for inflammasome activation. Intravital microscopy revealed that leukocytes rolled significantly slower in Nlrp3
venules than in Nlrp3
. Nlrp3
endothelial cells isolated from mesenteric vessels demonstrated a lower percentage of P-selectin-positive cells with lower intensity of surface P-selectin expression than the Nlrp3
endothelial cells evaluated by flow cytometry. We conclude that neutrophils orchestrate acute thioglycollate-induced peritonitis by producing IL-1β in an NLRP3-dependent manner. This increases endothelial P-selectin expression and leukocyte transmigration.
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Protein arginine deiminases (PAD) 4 is an enzyme that catalyzes citrullination of protein and its role in autoimmune diseases has been established through clinical genetics and gene knock out studies ...in mice. Further, studies with PAD4 - deficient mice have shown that PAD4 deficiency does not lead to increased infection or immune suppression, which makes PAD4 an attractive therapeutic target for auto-immune and inflammatory diseases. PAD4 has critical enzymatic role of promoting chromatin decondensation and neutrophil extracellular traps (NETs) formation that is associated with a number of immune-mediated pathological conditions. Here, we present a non-covalent PAD4 inhibitor JBI-589 with high PAD4 isoform selectivity and delineated its binding mode at 2.88 Å resolution by X-ray crystallography. We confirmed its effectiveness in inhibiting NET formation in vitro. Additionally, by using two mouse arthritis models for human rheumatoid arthritis (RA), the well-known disease associated with PAD4 clinically, we established its efficacy in vivo. These results suggest that JBI-589 would be beneficial for both PAD4 and NET-associated pathological conditions.
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Aim: The arterial pressure–volume index (API) and arterial velocity–pulse index (AVI) are novel measurement indices of arterial stiffness. This study was performed to examine the screening validity ...of the API and AVI for preclinical atherosclerosis in Japanese community-dwelling adults.Methods: We conducted a cross-sectional study of 2,809 participants aged ≥40 years who underwent Japanese national medical check-ups from 2014 to 2016. Preclinical atherosclerosis was defined as a mean carotid intima–media thickness (CIMT) of ≥1.0 mm. Multivariable linear regression analysis was performed to investigate the association of CIMT with API and AVI, adjusting for body mass index, sex, and the Framingham–D'Agostino score. We also examined receiver operating characteristic curves, sensitivity, and specificity to predict preclinical atherosclerosis defined by the CIMT. The cardio-ankle vascular index was also measured for comparison with the API and AVI.Results: Of 2,809 participants, 68 (2.4%) had preclinical atherosclerosis. In the multivariable linear regression analysis, the API and AVI maintained a positive association with the mean CIMT (B=2.6, P=0.009 and B=3.7, P=0.001, respectively). The cut-offs of the API and AVI that demonstrated better sensitivity and specificity for detection of subclinical atherosclerosis were 31 area under the curve (AUC), 0.64 and 29 (AUC, 0.60).Conclusions: The API and AVI were positively associated with preclinical carotid atherosclerosis independent of the participants' cardiovascular risk. The ability of these scores to predict carotid atherosclerosis could make them a useful screening tool for atherosclerosis.
Serum sodium concentration within the normal range could act as an indicator of age-related changes such as decrease in muscle strength and impairment of capillary function. Since endothelial injury ...stimulates endothelial repair by enhancing CD34-positive cell production, the level of serum sodium may be inversely associated with that of circulating CD34-positive cells, thus indicating the degree of age-related endothelial injury. We conducted a cross-sectional study of 246 elderly Japanese men aged 60-69 years. Subjects were stratified by hypertension status because hypertension should act as a strong confounding factor for the analyses performed in this study. Serum sodium concentration was positively associated with handgrip strength in non-hypertensive subjects standardized parameter estimate (β) = 0.29; p = 0.003, but not for hypertensive subjects (β = 0.01; p = 0.878), while it was inversely associated with circulating CD34-positive cell levels in non-hypertensive subjects simple correlation coefficient (r) = - 0.28; p = 0.002 but not for hypertensive subjects (r = - 0.07; p = 0.454). For non-hypertensive elderly subjects, serum sodium concentration within the normal range is positively associated with handgrip strength and inversely associated with CD34-positive cells, thus partly indicating the degree of age-related endothelium injury. These associations could prove to be an efficient tool for clarifying the background mechanism governing the decrease in age-related muscle strength.
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Objective
To clarify the significance of immunometabolism in systemic lupus erythematosus (SLE), and to determine the effect of calcium/calmodulin‐dependent protein kinase 4 (CaMK4) on T cell ...metabolism.
Methods
Metabolomic profiling was performed using capillary electrophoresis mass spectrometry in naive T cells from MRL/lpr mice treated with anti‐CD3/CD28 antibodies in the absence or presence of a CaMK4 inhibitor (KN‐93). The expression of GLUT1 and CaMK4 in CD4+ T cells from healthy controls (n = 16), patients with inactive SLE (n = 13), and patients with active SLE (n = 14) was examined by flow cytometry and quantitative polymerase chain reaction. In vitro experiments were performed to determine the effect of KN‐93 on the expression of GLUT1 during Th17 cell differentiation in T cells from patients with SLE.
Results
CaMK4 inhibition significantly decreased the levels of glycolytic intermediates such as glucose‐6‐phosphate, fructose‐6‐phosphate, fructose‐1,6‐diphosphate, pyruvate, and lactate (P < 0.05), whereas it did not affect the levels of the pentose phosphate pathway intermediates such as 6‐phospho‐d‐gluconate, ribulose‐5‐phosphate, ribose‐5‐phosphate, and phosphoribosyl pyrophosphate. The expression levels of GLUT1 and CaMK4 in effector memory CD4+ T cells were significantly higher in patients with active SLE compared to healthy controls (P < 0.01 and P < 0.05, respectively) and patients with inactive SLE (P < 0.05 and P < 0.01, respectively). A functional analysis revealed that CaMK4 inhibition decreased the expression of GLUT1 during Th17 cell differentiation (P < 0.01), followed by a reduction of interleukin‐17 (IL‐17) production (P < 0.05).
Conclusion
The results of the study indicate that the activity of CaMK4 could be responsible for glycolysis, which contributes to the production of IL‐17, and CaMK4 may contribute to aberrant expression of GLUT1 in T cells from patients with active SLE.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Age-related physical changes, such as low-grade inflammation and increased oxidative stress, induce endothelial repair and cause active arterial wall thickening by stimulating the production of CD34+ ...cells (the principal mediators of atherosclerosis). Despite this, aggressive endothelial repair (progressing atherosclerosis) might cause a wasting reduction in CD34+ cells, which could result in a lower capacity of endothelial repair and hypertension. As yet, no prospective study has clarified the association of circulating CD34+ cells with active arterial wall thickening. We conducted a prospective study of 363 men aged 60-69 years who participated in a general health check-up at least twice from 2014-2017. The circulating CD34+ cell count was significantly positively associated with active arterial wall thickening among subjects without hypertension (n = 236), but not among subjects with hypertension (n = 127). The fully adjusted odds ratios (ORs) of active arterial wall thickening for the logarithmic circulating CD34+ cell count were 1.83 (1.19, 2.84) and 0.69 (0.36, 1.32) for subjects without and with hypertension, respectively. Circulating CD34+ cells are positively associated with active arterial wall thickening in subjects without hypertension. This study demonstrates a means to clarify the mechanisms of endothelial repair in elderly subjects.
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