Stage-specific GATA3 induction promotes ILC2 development after lineage commitment.

Group 2 innate lymphoid cells (ILC2s) are a subset of innate lymphocytes that produce type 2 cytokines, including IL-4, IL-5, and IL-13. GATA3 is a critical transcription factor for ILC2 development at multiple stages. However, when and how GATA3 is induced to the levels required for ILC2 development remains unclear. Herein, we identify ILC2-specific GATA3-related tandem super-enhancers (G3SE) that induce high GATA3 in ILC2-committed precursors. G3SE-deficient mice exhibit ILC2 deficiency in the bone marrow, lung, liver, and small intestine with minimal impact on other ILC lineages or Th2 cells. Single-cell RNA-sequencing and subsequent flow cytometry analysis show that GATA3 induction mechanism, which is required for entering the ILC2 stage, is lost in IL-17RB+PD-1- late ILC2-committed precursor stage in G3SE-deficient mice. Cnot6l, part of the CCR4-NOT deadenylase complex, is a possible GATA3 target during ILC2 development. Our findings implicate a stage-specific regulatory mechanism for GATA3 expression during ILC2 development.

Combined evaluation of glomerular phospholipase A2 receptor and immunoglobulin G subclass in membranous nephropathy.

Background: Phospholipase A2 receptor (PLA2R) is a major target antigen in idiopathic membranous nephropathy (MN). Anti-PLA2R antibodies are mainly of the immunoglobulin G (IgG) subclass IgG4, although other IgG subclass depositions in glomeruli may also be detected. However, the importance of the subclass of the IgG deposit has not been proven. Thus we investigated clinical findings from patients with idiopathic MN in relation to glomerular PLA2R deposition and IgG subclass. Methods: We enrolled 132 Japanese patients with biopsy-proven idiopathic MN in a multicentre retrospective observational study. We investigated the complete remission rate as the primary outcome and the development of end-stage kidney disease (ESKD) as the secondary outcome in relation to glomerular PLA2R deposition. Moreover, we evaluated prognostic factors, including glomerular IgG subclass, in the PLA2R-positive group. Results: The percentage of cases with glomerular PLA2R deposition was 76.5% (n = 101). The first complete remission rate of the PLA2R-positive group was worse than that of the PLA2R-negative group (logrank test P < .001). ESKD incidence did not significantly differ between the glomerular PLA2R-negative and PLA2R-positive MN groups (logrank test P = .608). In the PLA2R-positive group, higher PLA2R intensities and IgG2 staining were associated with a poorer first complete remission rate (logrank test P < .001 and P = .032, respectively). Cox proportional hazards analysis also showed that strong PLA2R deposition and positive IgG2 staining were significantly associated with a failure to reach complete remission [hazard ratio 2.09 (P = .004) and 1.78 (P = .030), respectively]. Conclusions: Our results suggest that intense glomerular PLA2R and IgG2 positivity predict a poor proteinuria remission rate in idiopathic MN.

A distal enhancer of GATA3 regulates Th2 differentiation and allergic inflammation.

Asthma is a widespread airway disorder where GATA3-dependent Type-2 helper T (Th2) cells and group 2 innate lymphoid cells (ILC2s) play vital roles. Asthma-associated single nucleotide polymorphisms (SNPs) are enriched in a region located 926-970 kb downstream from GATA3 in the 10p14 (hG900). However, it is unknown how hG900 affects the pathogenesis of allergic airway inflammation. To investigate the roles of the asthma-associated GATA3 enhancer region in experimental allergic airway inflammation, we first examined the correlation between GATA3 expression and the activation of the hG900 region was analyzed by flow cytometry and ChIP-qPCR. We found that The activation of enhancers in the hG900 region was strongly correlated to the levels of GATA3 in human peripheral T cell subsets. We next generated mice lacking the mG900 region (mG900KO mice) were generated by the CRISPR-Cas9 system, and the development and function of helper T cells and ILCs in mG900KO mice were analyzed in steady-state conditions and allergic airway inflammation induced by papain or house dust mite (HDM). The deletion of the mG900 did not affect the development of lymphocytes in steady-state conditions or allergic airway inflammation induced by papain. However, mG900KO mice exhibited reduced allergic inflammation and Th2 differentiation in the HDM-induced allergic airway inflammation. The analysis of the chromatin conformation around Gata3 by circular chromosome conformation capture coupled to high-throughput sequencing (4C-seq) revealed that the mG900 region interacted with the transcription start site of Gata3 with an influencing chromatin conformation in Th2 cells. These findings indicate that the mG900 region plays a pivotal role in Th2 differentiation and thus enhances allergic airway inflammation.

Associations between the Serum Triglyceride Level and Kidney Outcome in Patients with Chronic Kidney Disease: The Fukuoka Kidney disease Registry Study.

AIMS: Hypertriglyceridemia is a risk factor for chronic kidney disease (CKD). However, whether or not it predicts the risk of CKD progression is unknown. This study evaluated the association between serum triglyceride (TG) levels and kidney disease progression in patients with non-dialysis-dependent CKD. METHODS: The Fukuoka Kidney disease Registry (FKR) study was a multicenter, prospective longitudinal cohort study. In total, 4,100 patients with CKD were followed up for 5 years. The primary outcome was the incidence of CKD progression, defined as a ≥ 1.5-fold increase in serum creatinine level or the development of end-stage kidney disease. The patients were divided into quartiles according to baseline serum TG levels under non-fasting conditions: Q1 ＜87 mg/dL; Q2, 87-120 mg/dL; Q3, 121-170 mg/dL, and Q4 ＞170 mg/dL. RESULTS: During the 5-year observation period, 1,410 patients met the criteria for CKD progression. The multivariable-adjusted Cox proportional hazards model showed a significant association between high serum TG level and the risk of CKD progression in the model without macroalbuminuria as a covariate (multivariable hazard ratio[HR] for Q4 versus Q1, 1.20; 95% CI, 1.03-1.41; P=0.022), but the significance disappeared after adjusting for macroalbuminuria (HR for Q4 versus Q1, 1.06; 95% CI, 0.90-1.24; P=0.507). CONCLUSIONS: The present findings suggest that individuals with high serum TG levels are more likely to develop CKD progression than those without; however, whether or not higher serum TG levels reflect elevated macroalbuminuria or lead to CKD progression via elevated macroalbuminuria is unclear.

Impact of Age on Prescribing Patterns of Cardiovascular Medications in Older Japanese Patients with Non-Dialysis-Dependent Chronic Kidney Disease: A Cross-Sectional Study.

AIM: Older patients with chronic kidney disease (CKD) are more likely to be excluded from clinical trials. This exclusion affects the quality of cardiovascular disease (CVD) prevention in this population. METHODS: Baseline data from the Fukuoka Kidney Disease Registry (FKR) cohort, which included 4476 adult patients with CKD stages G1-G5, were cross-sectionally analyzed to compare the use of recommended drugs for preventing CVD in each age group. RESULTS: Different prescribing patterns were observed according to age for the cardiovascular drug classes. Older patients with CKD were less likely to receive renin-angiotensin system (RAS) inhibitors and were more likely to receive calcium channel blockers. The proportion of anticoagulation prescriptions for patients with CKD and atrial fibrillation decreased in the older age group (≥ 75 years). However, the proportion of antiplatelet therapy in patients with ischemic CVD increased linearly with age, even in the very old group aged ≥ 85 years. These findings suggest a severe cardiovascular burden in patients with CKD. Notably, RAS inhibitor use was avoided in the older group despite a severe cardiovascular burden, such as a high prevalence of CVD history and massive albuminuria ＞300 mg/g creatinine. This finding indicates that an older age independently contributed to the non-use of RAS inhibitors, even after adjusting for other covariates. CONCLUSIONS: This study suggests that age is a potential barrier to the treatment of patients with CKD and highlights the need to establish individualized treatment strategies for cardiovascular protection in this population.

Association between glycated albumin and sudden death in patients undergoing hemodialysis.

BACKGROUND: The frequency of sudden death and its risk factors in patients undergoing hemodialysis are unknown. This study was performed to examine the association between glycated albumin (GA) and sudden death in Japanese patients undergoing hemodialysis. METHODS: In total, 260 patients undergoing hemodialysis aged ≥18 years were retrospectively followed for a mean of 4.6 years. The patients' serum GA levels were divided into tertiles, and the patients' sex, age, albumin level, C-reactive protein (CRP) level, and cardiothoracic ratio (CTR) were selected as adjustment factors. A logistic regression model was used to calculate the odds ratio (OR) for the occurrence of sudden death by GA level. RESULTS: Ninety-one patients died during follow-up. Of the 91 deaths, 23 (25.2%) were defined as sudden deaths. Compared with non-sudden death cases, sudden death cases were significantly younger (p = 0.002) and had a higher proportion of men (p = 0.03), a higher proportion of diabetes (p = 0.008), and higher GA levels (p = 0.023). Compared with patients with the lowest GA levels (<15.2%), those with the highest GA levels (≥18.5%) had a sex- and age-adjusted OR for sudden death of 5.40 [95% confidence interval (CI): 1.35-21.85]. After adjusting for the albumin level, CRP level, and CTR in addition to sex and age, the OR for sudden death of patients with the highest GA levels increased to 6.80 (95%CI: 1.64-28.08); the relationship did not change. CONCLUSION: Serum GA levels were significantly associated with sudden death in patients undergoing hemodialysis.

History of fragility fracture is associated with cardiovascular mortality in hemodialysis patients: the Q-Cohort study.

INTRODUCTION: In patients undergoing dialysis, major bone fracture is associated with a high risk of mortality, including death of cardiovascular (CV) origin. In the present study, we aimed to determine whether a history of fragility fracture is a predictor of CV death in patients undergoing hemodialysis with long-term follow-up. MATERIALS AND METHODS: In total, 3499 patients undergoing hemodialysis were analyzed for 10 years. We evaluated the history of fragility fracture in each patient at enrollment. The primary outcome was CV death. A Cox proportional hazard model and a competing risk approach were applied to determine the association between a history of fragility fracture and CV death. RESULTS: A total of 346 patients had a history of fragility fracture at enrollment. During a median follow-up of 8.8 years, 1730 (49.4%) patients died. Among them, 621 patients experienced CV death. Multivariable Cox analyses after adjustment for confounding variables showed that a history of fragility fracture was associated with CV death (hazard ratio, 1.47; 95% confidence interval, 1.16-1.85). In the Fine-Gray regression model, a history of fragility fracture was an independent risk factor for CV death (subdistribution hazard ratio, 1.36; 95% confidence interval, 1.07-1.72). CONCLUSION: In a large cohort of patients undergoing hemodialysis, a history of fragility fracture was an independent predictor of CV death.

Physiological and immunological barriers in the lung.

The lungs serve as the primary organ for respiration, facilitating the vital exchange of gases with the bloodstream. Given their perpetual exposure to external particulates and pathogens, they possess intricate protective barriers. Cellular adhesion in the lungs is robustly maintained through tight junctions, adherens junctions, and desmosomes. Furthermore, the pulmonary system features a mucociliary clearance mechanism that synthesizes mucus and transports it to the outside. This mucus is enriched with chemical barriers like antimicrobial proteins and immunoglobulin A (IgA). Additionally, a complex immunological network comprising epithelial cells, neural cells, and immune cells plays a pivotal role in pulmonary defense. A comprehensive understanding of these protective systems offers valuable insights into potential pathologies and their therapeutic interventions.

Association between Hemoglobin A1c and Renal Arteriolar Sclerosis in Subjects Presenting without any Apparent Kidney Dysfunction.

AIMS: Diabetic kidney disease is a major vascular complication in patients with diabetes mellitus (DM). However, the association between the hemoglobin (Hb)A1c levels, notably the prediabetic levels, and renal pathological changes remains unclear. We investigated the association between the HbA1c levels and renal arteriolar lesions in subjects without any apparent kidney dysfunction using a living kidney donor cohort. METHODS: Between January 2006 and May 2016, 393 living kidney donors underwent a "zero-time" biopsy at Kyushu University Hospital. The patients were divided into four groups (HbA1c levels ＜5.6%, 5.6%-5.7%, 5.8%-6.4%, and ≥ 6.5%, or diagnosed with DM [DM group]). Renal arteriolar hyalinization and wall thickening were assessed using semi-quantitative grading. We then investigated the association between the HbA1c levels and renal pathological changes. RESULTS: 158 (40.2%) patients had arteriolar hyalinization and 148 (37.6%) showed wall thickening. A significant correlation was observed between the HbA1c levels and wall thickening (p for trend ＜0.001). An elevated HbA1c level was significantly associated with wall thickening according to a multivariable logistic analysis in subjects with HbA1c levels of 5.6%-5.7% and 5.8%-6.4%, and the DM group, compared with those with HbA1c levels of ＜5.6% (odds ratio [OR], 1.91; 95% confidence interval [CI]: [1.03-3.54] for 5.6%-5.7%, OR, 1.96; 95% CI: [1.09-3.53] for 5.8%-6.4%, and OR, 2.86; 95% CI: [0.91-9.01] for the DM group), whereas arteriolar hyalinization did not increase within the nondiabetic HbA1c levels. CONCLUSIONS: Elevated high-normal HbA1c levels are considered to be independent risk factors for arteriolar wall thickening. Subclinical renal arteriolar sclerosis may develop in patients with prediabetic HbA1c levels.

Single-cell RNA sequencing of submandibular gland reveals collagen type XV-positive fibroblasts as a disease-characterizing cell population of IgG4-related disease.

OBJECTIVES: IgG4-related disease (IgG4-RD) is a systemic autoimmune disease with an unknown etiology, affecting single/multiple organ(s). Pathological findings include the infiltration of IgG4-producing plasma cells, obliterative phlebitis, and storiform fibrosis. Although immunological studies have shed light on the dysregulation of lymphocytes in IgG4-RD pathogenesis, the role of non-immune cells remains unclear. This study aimed to investigate the demographics and characteristics of non-immune cells in IgG4-RD and explore potential biomarkers derived from non-immune cells in the sera. METHODS: We conducted single-cell RNA sequence (scRNA-seq) on non-immune cells isolated from submandibular glands of IgG4-RD patients. We focused on fibroblasts expressing collagen type XV and confirmed the presence of those fibroblasts using immunohistochemistry. Additionally, we measured the levels of collagen type XV in the sera of IgG4-RD patients. RESULTS: The scRNA-seq analysis revealed several distinct clusters consisting of fibroblasts, endothelial cells, ductal cells, and muscle cells. Differential gene expression analysis showed upregulation of COL15A1 in IgG4-RD fibroblasts compared to control subjects. Notably, COL15A1-positive fibroblasts exhibited a distinct transcriptome compared to COL15A1-negative counterparts. Immunohistochemical analysis confirmed a significant presence of collagen type XV-positive fibroblasts in IgG4-RD patients. Furthermore, immune-suppressive therapy in active IgG4-RD patients resulted in decreased serum levels of collagen type XV. CONCLUSIONS: Our findings suggest that collagen type XV-producing fibroblasts may represent a disease-characterizing non-immune cell population in IgG4-RD and hold potential as a disease-monitoring marker.

Relationships of Weight Change from 20 Years of Age with the Risks of All-Cause and Cardiovascular Mortality in Patients with Chronic Kidney Disease.

AIMS: Weight changes from a young age are known to be associated with poor life outcomes in the general population. However, little is known about the association between weight change from a young age and life expectancy in patients with chronic kidney disease (CKD). METHODS: Data of 2,806 nondialysis CKD patients who participated in the Fukuoka Kidney Disease Registry (FKR) Study, a multicenter observational study, were analyzed. The primary outcome was all-cause death, whereas the secondary outcome was cardiovascular mortality. The covariate of interest was weight change, defined as the difference between body weight at study enrollment and at 20 years old. Cox proportional-hazards models were used to estimate the risks of mortality for participants with weight changes of ≥ 5 or ＜5 kg compared with those with stable weights. RESULTS: During the 5-year observation period, 243 participants died from all causes and 62 from cardiovascular disease. The risk of all-cause mortality in the weight-loss group was significantly higher than that in the stable-weight group (multivariable-adjusted hazard ratio, 2.11; 95% confidence interval [CI], 1.52-2.93). Conversely, the risk of cardiovascular mortality in the weight-loss group was significantly higher than that in the stable-weight group (multivariable-adjusted hazard ratio, 2.48; 95% CI, 1.32-4.64). However, no significant association was observed between weight gain and the risks of all-cause and cardiovascular mortalities. CONCLUSION: Weight loss from 20 years of age was found to be associated with higher risks of all-cause and cardiovascular mortalities in patients with CKD.

Eosinophils Contribute to Oral Tolerance via Induction of RORγt-Positive Antigen-Presenting Cells and RORγt-Positive Regulatory T Cells.

Oral tolerance has been defined as the specific suppression of immune responses to an antigen by prior oral administration of the antigen. It has been thought to serve to suppress food allergy. Previous studies have shown that dendritic cells (DCs) and regulatory T cells (Tregs) are involved in the induction of oral tolerance. However, the detailed mechanisms of Treg induction in oral tolerance remain largely unknown. Eosinophils have been recognized as effector cells in allergic diseases, but in recent years, the diverse functions of tissue-resident eosinophils have been reported. Eosinophils in the intestine have been reported to induce Tregs by releasing TGF-ß, but the role of eosinophils in oral tolerance is still controversial. In this study, we analyzed the roles of eosinophils in oral tolerance using eosinophil-deficient ΔdblGATA mice (mice lacking a high-affinity GATA-binding site in the GATA1 promoter). ΔdblGATA mice showed impaired antigen-induced oral tolerance compared to wild-type mice. The induction of RORγt+ Tregs in mesenteric lymph nodes (MLNs) by oral tolerance induction was impaired in ΔdblGATA mice compared to wild-type mice. An increase in RORγt+ antigen-presenting cells (APCs), which are involved in RORγt+ Treg differentiation, in the intestine and MLNs was not seen in ΔdblGATA mice. Notably, the expansion of group 3 innate lymphoid cells (ILC3s), a subset of RORγt+ APCs, by oral tolerance induction was seen in wild-type mice but not ΔdblGATA mice. These results suggest that eosinophils are crucial in the induction of oral tolerance, possibly via the induction of RORγt+ APCs and RORγt+ Tregs.

More rapid progression of brain atrophy in patients on peritoneal dialysis compared with hemodialysis: The VCOHP Study.

We previously reported that brain atrophy was more severe and progressed more rapidly in patients with end-stage kidney disease on peritoneal dialysis (PD) than those with non-dialysis-dependent chronic kidney disease. However, it remains unknown whether there is a difference between patients on PD and hemodialysis (HD). In total, 73 PD and 34 HD patients who underwent brain magnetic resonance imaging (MRI) were recruited for a cross-sectional analysis. Among them, 42 PD and 25 HD patients who underwent a second brain MRI after 2 years were recruited for a longitudinal analysis. T1-weighted MRI images were analyzed. Total gray matter volume (GMV), total white matter volume, and cerebrospinal fluid volume were segmented, and each volume was quantified using statistical parametric mapping software. The ratio of GMV (GMR) was calculated by dividing GMV by intracranial volume, to adjust for variations in head size. We compared GMR between PD and HD patients in the cross-sectional analysis and the annual change in GMR (AC-GMR) in the longitudinal analysis. In the cross-sectional analysis, age- and sex-adjusted GMR was significantly lower in PD than HD patients [least square mean (LSM): 39.2% vs. 40.0%, P = 0.018]. AC-GMR was significantly greater in PD than HD patients and this difference remained significant even after adjustment for potential confounding factors (LSM: -0.68 vs. -0.28 percentage-points/year, P = 0.011). In conclusion, the present study demonstrated a more rapid progression of brain atrophy in PD patients compared with HD patients. We demonstrated that decline in GMR progressed significantly more rapidly in PD than HD patients independent of potential confounding factors. GMR gray matter volume ratio, HD hemodialysis, PD peritoneal dialysis.

IL-21 is required for the maintenance and pathogenesis of murine Vγ4+ IL-17-producing γδT cells.

Murine IL-17-producing γδT (γδT17) cells are divided into two subsets: natural γδT17 (nγδT17) cells, whose development is restricted to the fetal thymus, and inducible γδT17 cells, which require antigen exposure for their IL-17 production and are presumed to develop from Rorc + Il17a - CCR9 + immature γδT17 cells in the adult thymus and whose T cell receptor (TCR) is biased toward Vγ4. Although IL-23 is known to be involved in developing γδT17 cells, the roles of other cytokines, such as IL-21, which is involved in developing Th17 cells like IL-23, in the development, maintenance, and pathophysiology of γδT17 cells remain unknown. Here, we show that IL-21 is dispensable for the fetal thymic development of nγδT17 cells but is required for the peripheral maintenance of Vγ4+nγδT17 cells. Upon stimulation with γδTCR, IL-1 plus IL-21 induces the proliferation of Vγ4+nγδT17 cells via STAT3 as effectively as IL-1 plus IL-23. Using bone marrow chimeric mice, we demonstrated that immature γδT17 cells are produced de novo in the adult mice from donor adult bone marrow cells and that IL-21 is dispensable for their development. Instead, IL-21 is required to expand newly induced Vγ4+γδT17 cells in the periphery upon immunization. Finally, using adoptive transfer experiments of γδT17 cells, we found that IL-21 receptors on γδT17 cells are involved in maintaining Vγ4+γδT17 cells, subsequent infiltration of Th17 cells into the spinal cord, and exacerbation of experimental autoimmune encephalomyelitis. Collectively, IL-21 plays a vital role in the maintenance and pathogenesis of Vγ4+γδT17 cells.

Prevalence of hyponatremia and associated factors in patients with chronic kidney disease: the Fukuoka Kidney Disease Registry (FKR) study.

BACKGROUND: Hyponatremia is a common and important electrolyte disorder. However, the prevalence and factors associated with hyponatremia in patients with chronic kidney disease (CKD) are unknown. METHODS: We studied the factors associated with hyponatremia (< 135 mEq/L) in CKD patients registered in the Fukuoka Kidney Disease Registry (FKR) study using a logistic regression model variable selected using the variable reduction method. RESULTS: We analyzed the baseline characteristics of 4367 participants with CKD (age, 64 ± 16 years; male, 56.1%). Hyponatremia was detected in 2.0% of the patients at baseline, and multivariate logistic analysis showed that the independent factors for hyponatremia were body mass index (odds ratio [OR] 0.91; 95% confidence interval [CI] 0.85-0.97), prescription of benzodiazepine (OR 2.31; 95% CI 1.39-3.86), blood hemoglobin level (OR 0.76; 95% CI 0.65-0.88), and serum C-reactive protein level (OR 1.27; 95% CI 1.04-1.54). CONCLUSION: The cross-sectional analysis using baseline data from the FKR study revealed independent factors associated with hyponatremia in patients with decreased kidney function. Longitudinal analyses of the FKR cohort are needed to evaluate the effects of these factors on the prognosis of hyponatremia in patients with CKD.

Angiotensin II receptor blockers and bone fracture in chronic kidney disease patients: the Fukuoka kidney disease Registry Study.

BACKGROUND: Angiotensin II receptor blockers (ARBs) reportedly reduce the risk of developing bone fractures; however, this association remains unclear among patients with chronic kidney disease (CKD). METHODS: This was a cross-sectional study of 3380 CKD patients enrolled in the Fukuoka Kidney disease Registry Study, a multicenter prospective observational cohort study of non-dialysis-dependent CKD patients. The patients were divided into two groups, those taking ARBs and those who were not. Logistic regression models were used to examine the association between ARBs and bone fracture. RESULTS: Approximately 67.0% of the participants were on ARBs, and 6.3% had a history of bone fracture. The history of bone fracture was significantly lower in patients with prescribed ARB and remained significant even after multivariable adjustment (odds ratio, 0.68; 95% confidence interval, 0.51-0.93). Other antihypertensive drugs, such as thiazide diuretics, which were reportedly helpful in preventing fractures, did not alter the bone fracture history and did not change among ARB users and non-users. CONCLUSIONS: The present study showed that administering ARB was significantly associated with a lower frequency of bone fracture history.

CCR4 predicts the efficacy of abatacept in rheumatoid arthritis patients through the estimation of Th17 and Treg cell abundance.

OBJECTIVE: Predicting the efficacy of biological disease-modifying anti-rhematic drugs (bDMARDs) is challenging. In this study, we aimed to explore markers that predict the efficacy of abatacept in rheumatoid arthritis (RA) patients. METHODS: Thirty RA patients receiving abatacept were recruited, and peripheral blood mononuclear cells (PBMCs) from the participants were subjected to DNA microarray analysis. The expression of CCR4, which was selected by the result of DNA microarray, was determined by flow cytometry in 16 newly diagnosed treatment-naïve RA patients. CCR4 expression on each helper T cell subset was also measured. RESULTS: CCR4 was upregulated in the abatacept responder. The expression levels of CCR4 were significantly correlated with the improvement of clinical disease activity index (CDAI). CCR4 expression was predominantly observed in CD4+ T cells in PBMCs. The percentage of CCR4-expressing CD4+ T cells was significantly higher in RA patients than in healthy individuals. Interestingly, Th17 and Treg cells expressed high levels of CCR4 compared to non-Th17-related helper T cells. CONCLUSION: CCR4 is a Th17- and Treg-related gene, and the high CCR4 expression in peripheral blood samples may predict the efficacy of abatacept in RA.

P2Y2 receptor mediates dying cell removal via inflammatory activated microglia.

Microglial removal of dying cells plays a beneficial role in maintaining homeostasis in the CNS, whereas under some pathological conditions, inflammatory microglia can cause excessive clearance, leading to neuronal death. However, the mechanisms underlying dying cell removal by inflammatory microglia remain poorly understood. In this study, we performed live imaging to examine the purinergic regulation of dying cell removal by inflammatory activated microglia. Lipopolysaccharide (LPS) stimulation induces rapid death of primary rat microglia, and the surviving microglia actively remove dying cells. The nonselective P2 receptor antagonist, suramin, inhibited dying cell removal to the same degree as that of the selective P2Y2 antagonist, AR-C118925. This inhibition was more potent in LPS-stimulated microglia than in non-stimulated ones. LPS stimulation elicited distribution of the P2Y2 receptor on the leading edge of the plasma membrane and then induced drastic upregulation of P2Y2 receptor mRNA expression in microglia. LPS stimulation caused upregulation of the dying cell-sensing inflammatory Axl phagocytic receptor, which was suppressed by blocking the P2Y2 receptor and its downstream signaling effector, proline-rich tyrosine kinase (Pyk2). Together, these results indicate that inflammatory stimuli may activate the P2Y2 receptor, thereby mediating dying cell removal, at least partially, through upregulating phagocytic Axl in microglia.

A role of Achaete-scute complex homolog 2 in T follicular regulatory cell development.

T follicular regulatory (Tfr) cells, a subset of CD4+ Foxp3+ regulatory T (Treg) cells, locate to the lymphoid follicle and germinal center (GC) and regulate antibody responses. Tfr cells express the functional molecules of follicular helper T (Tfh) cells, including CXCR5 and Bcl6. CD25- mature Tfr cells differentiate from CD25+ Treg cells through CD25+ immature Tfr cells. Others and we have shown that Achaete-scute complex homolog 2 (Ascl2) plays a role in Tfh cell development; however, the role of Ascl2 in the development of Tfr cells remains unclear. Here, we found that Ascl2 was highly and preferentially expressed in CD25+ Tfr cells and CD25- Tfr cells, and that the differentiation from CD25+ Tfr cells to CD25- Tfr cells was impaired by the absence of Ascl2. Furthermore, the forced Ascl2 expression in Treg cells downregulated CD25 expression and suppressed IL-2-induced phosphorylation of STAT5, which is known to suppress CD25- Tfr cell development. Finally, we found that the downregulation of CD25 by Ascl2 in Treg cells is independent of Bach2, which also regulates CD25 downregulation in CD25+ Tfr cells. These results suggest that Ascl2 plays a vital role in developing Tfr cells, possibly by downregulating CD25 expression in a Bach2-independent mechanism.