Downregulation of the phosphatase JKAP/DUSP22 in T cells as a potential new biomarker of systemic lupus erythematosus nephritis

Circulating JKAP levels may correlate with postpartum anxiety and depression through its interaction with T helper 17 cells

Jun N-terminal kinase pathway-associated phosphatase (JKAP) regulates CD4+ T-cell differentiation and immunity, which are linked to mental disorders. This study aimed to explore the relationships between JKAP and T helper 17 (Th17)/regulatory T (Treg) ratio, as well as their associations with anxiety and depression in postpartum women. Serum JKAP were measured by enzyme-linked immunosorbent assay and blood Th17 and Treg cells were measured by flow cytometry in 250 postpartum women. Anxiety and depression were evaluated by the 6-item State-Trait Anxiety Inventory (STAI6) and Edinburgh Postnatal Depression Scale (EPDS). Anxiety and depression rates were 22.0 and 28.4%, respectively, among postpartum women. Notably, JKAP was negatively associated with the STAI6 (P=0.002) and EPDS scores (P<0.001) in postpartum women and was lower in postpartum women with anxiety (P=0.023) or depression (P=0.002) than in those without. Moreover, JKAP was inversely related to Th17 cells and Th17/Treg ratio but positively correlated with Treg cells in postpartum women (all P<0.001). Interestingly, Th17 cells and Th17/Treg ratio were both positively associated with STAI6 and EPDS scores in postpartum women (all P<0.001). Furthermore, Th17 cells and Th17/Treg ratio were lower in postpartum women with anxiety or depression than in those without (all P<0.01). Nevertheless, Treg cells were not linked to anxiety or depression in postpartum women. JKAP was negatively associated with Th17 cells and Th17/Treg ratio; moreover, they all related to anxiety and depression in postpartum women, indicating that JKAP may be involved in postpartum anxiety and depression via interactions with Th17 cells.

UHRF1P contributes to IL-17A-mediated systemic lupus erythematosus via UHRF1-MAP4K3 axis

Inflammatory T cells contribute to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Analysis of the T-cell transcriptomics data of two independent SLE patient cohorts by three machine learning models revealed the pseudogene UHRF1P as a novel SLE biomarker. The pseudogene-encoded UHRF1P protein was overexpressed in peripheral blood T cells of SLE patients. The UHRF1P protein lacks the amino-terminus of its parental UHRF1 protein, resulting in missing the proteasome-binding ubiquitin-like (Ubl) domain of UHRF1. T-cell-specific UHRF1P transgenic mice manifested the induction of IL-17A and autoimmune inflammation. Mechanistically, UHFR1P prevented UHRF1-induced Lys48-linked ubiquitination and degradation of MAP4K3 (GLK), which is a kinase known to induce IL-17A. Consistently, IL-17A induction and autoimmune phenotypes of UHRF1P transgenic mice were obliterated by MAP4K3 knockout. Collectively, UHRF1P overexpression in T cells inhibits the E3 ligase function of its parental UHRF1 and induces autoimmune diseases.

The phosphatase DUSP22 inhibits UBR2-mediated K63-ubiquitination and activation of Lck downstream of TCR signalling

DUSP22 is a dual-specificity phosphatase that inhibits T cell activation by inactivating the kinase Lck. Here we show that the E3 ubiquitin ligase UBR2 is a positive upstream regulator of Lck during T-cell activation. DUSP22 dephosphorylates UBR2 at specific Serine residues, leading to ubiquitin-mediated UBR2 degradation. UBR2 is also modified by the SCF E3 ubiquitin ligase complex via Lys48-linked ubiquitination at multiple Lysine residues. Single-cell RNA sequencing analysis and UBR2 loss of function experiments showed that UBR2 is a positive regulator of proinflammatory cytokine expression. Mechanistically, UBR2 induces Lys63-linked ubiquitination of Lck at Lys99 and Lys276 residues, followed by Lck Tyr394 phosphorylation and activation as part of TCR signalling. Inflammatory phenotypes induced by TCR-triggered Lck activation or knocking out DUSP22, are attenuated by genomic deletion of UBR2. UBR2-Lck interaction and Lck Lys63-linked ubiquitination are induced in the peripheral blood T cells of human SLE patients, which demonstrate the relevance of the UBR2-mediated regulation of inflammation to human pathology. In summary, we show here an important regulatory mechanism of T cell activation, which finetunes the balance between T cell response and aggravated inflammation.

Serum JKAP reflects Th2 and Th17 cell levels, and diabetic nephropathy risk and severity in diabetes mellitus patients

Objective: This study aimed to explore the potency of serum JKAP for estimating diabetic nephropathy risk in diabetes mellitus (DM) patients. Methods: Serum JKAP was detected in 212 DM patients. According to urinary albumin-to-creatinine ratio, DM patients were divided into normoalbuminuria, microalbuminuria and macroalbuminuria groups. Results: JKAP declined in the macroalbuminuria group versus normoalbuminuria group (p < 0.001). In DM patients, JKAP inversely correlated with Th17 cells (p < 0.001) but positively related to Th2 cells (p = 0.003). After adjustment, JKAP independently estimated lower risks of albuminuria (microalbuminuria + macroalbuminuria; odds ratio = 0.966, p < 0.001) and macroalbuminuria (odds ratio = 0.948; p = 0.002). Conclusion: Serum JKAP reflects increased Th2 cells, decreased Th17 cells, and lower diabetic nephropathy risk and severity in DM patients.

Primary Cutaneous Anaplastic Large Cell Lymphoma-A Review of Clinical, Morphological, Immunohistochemical, and Molecular Features

Primary cutaneous anaplastic large cell lymphoma (ALCL) is the second most common cutaneous T-cell lymphoma after mycosis fungoides and belongs to the spectrum of cutaneous CD30+ T-cell lymphoproliferative disorders. Although primary cutaneous ALCL usually presents as a localized nodule or papule with or without ulceration, multifocal lesions may occur in up to 20% of cases. Histologically, primary cutaneous ALCL consists of a diffuse dermal infiltrate of medium to large anaplastic/pleomorphic cells with abundant amphophilic-to-eosinophilic cytoplasm, horseshoe-shaped nuclei, strong and diffuse expression of CD30, and with focal or no epidermotropism. The neoplastic infiltrate may show angiocentric distribution and may extend to the subcutis. Patients with localized or multifocal disease have a similar prognosis with a 10-year overall survival rate of 90%. Approximately 30% of primary cutaneous ALCLs harbor a DUSP22 (6p25.3) gene rearrangement that results in decreased expression of this dual-specific phosphatase, decreased STAT3 activation, and decreased activity of immune and autoimmune-mediated mechanisms regulated by T-cells.

DUSP2 inhibits the progression of lupus nephritis in mice by regulating the STAT3 pathway

One of the most severe side effects of systemic lupus erythematosus (SLE) is lupus nephritis (LN). To search for potential therapeutic targets in SLE is crucial for the progression of SLE. In this study, we selected C57BL/6J mice as controls and MRL/lpr mice as an LN model and obtained dual specificity phosphatase 2 (DUSP2)-overexpressed mice by injecting AAV-DUSP2 plasmid into the tail vein. Then, proteinuria, urea nitrogen, dsDNA and TNF-α, IL-6, and IL-1β levels were measured in each group of mice. In addition, renal histopathological damage was assessed by hematoxylin-eosin. Finally, STAT3 phosphorylation levels were detected by Western blot assay. The results showed that DUSP2 could reduce proteinuria, urea nitrogen, dsDNA and TNF-α, IL-6, and IL-1β levels and improve renal tissue injury in mice with LN. Mechanistically, DUSP2 inhibited STAT3 phosphorylation. These results demonstrated that DUSP2 played a role in ameliorating LN, which provided potential targets for LN research.

Targeting protein phosphatases in cancer immunotherapy and autoimmune disorders

Protein phosphatases act as key regulators of multiple important cellular processes and are attractive therapeutic targets for various diseases. Although extensive effort has been dedicated to phosphatase-targeted drug discovery, early expeditions for competitive phosphatase inhibitors were plagued by druggability issues, leading to the stigmatization of phosphatases as difficult targets. Despite challenges, persistent efforts have led to the identification of several drug-like, non-competitive modulators of some of these enzymes - including SH2 domain-containing protein tyrosine phosphatase 2, protein tyrosine phosphatase 1B, vascular endothelial protein tyrosine phosphatase and protein phosphatase 1 - reigniting interest in therapeutic targeting of phosphatases. Here, we discuss recent progress in phosphatase drug discovery, with emphasis on the development of selective modulators that exhibit biological activity. The roles and regulation of protein phosphatases in immune cells and their potential as powerful targets for immuno-oncology and autoimmunity indications are assessed.

Dual-specificity phosphatases 22-deficient T cells contribute to the pathogenesis of ankylosing spondylitis

BACKGROUND

Dual-specificity phosphatases (DUSPs) can dephosphorylate both tyrosine and serine/threonine residues of their substrates and regulate T cell-mediated immunity and autoimmunity. The aim of this study was to investigate the potential roles of DUSPs in ankylosing spondylitis (AS).

METHODS

Sixty AS patients and 45 healthy controls were enrolled in this study. Associations of gene expression of 23 DUSPs in peripheral T cells with inflammatory cytokine gene expression and disease activity of AS were analyzed. Finally, we investigated whether the characteristics of AS are developed in DUSP-knockout mice.

RESULTS

The mRNA levels of DUSP4, DUSP5, DUSP6, DUSP7, and DUSP14 in peripheral T cells were significantly higher in AS group than those of healthy controls (all p < 0.05), while DUSP22 (also named JKAP) mRNA levels were significantly lower in AS group than healthy controls (p < 0.001). The mRNA levels of DUSP4, DUSP5, DUSP6, DUSP7, and DUSP14 in T cells were positively correlated with mRNA levels of tumor necrosis factor-α (TNF-α), whereas DUSP22 was inversely correlated (all p < 0.05). In addition, inverse correlations of DUSP22 gene expression in peripheral T cells with C-reactive protein, erythrocyte sedimentation rate, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were observed (all p < 0.05). More importantly, aged DUSP22 knockout mice spontaneously developed syndesmophyte formation, which was accompanied by an increase of TNF-α⁺, interleukin-17A⁺, and interferon-γ⁺ CD3⁺ T cells.

CONCLUSIONS

DUSP22 may play a crucial role in the pathogenesis and regulation of disease activity of AS.

Dual specificity phosphatase 22 suppresses mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK signaling pathway in diabetic nephropathy

Dual specificity phosphatase 22 (DUSP22) regulates fibrosis and inflammation, which may be implicated in the development of diabetic nephropathy (DN). Hence, the current study aimed to assess the effect of DUSP22 on cell proliferation, apoptosis, fibrosis and inflammation in mouse mesangial cell line (SV40-MES13) under both high glucose (HG) and low glucose (LG) conditions. SV40-MES13 cells were treated with HG and LG, then HG-group cells were transfected with DUSP22 overexpression and control plasmids, meanwhile LG-group cells were transfected with DUSP22 and control siRNAs. Then, cell proliferation using Cell Counting Kit-8, cell apoptosis by TUNEL assay, protein expression using western blotting, inflammatory cytokines using ELISA and RNA using reverse transcription-quantitative PCR were determined. DUSP22 mRNA and protein were decreased in SV40-MES13 cells under the HG condition compared with those under the LG condition. Under the HG condition, DUSP22 overexpression suppressed SV40-MES13 cell proliferation at 48 and 72 h as well as Bcl2, but it facilitated TUNEL-reflected apoptotic rate and cleaved-caspase-3; besides, DUSP22 overexpression restrained proteins of fibronectin 1, collagen I, transforming growth factor beta 1, and their corresponding mRNAs. As to the inflammation, DUSP22 overexpression downregulated TNF-α, IL-1β, IL-6 and IL-12 under the HG condition. By contrast, DUSP22 siRNA promoted SV40-MES13 cell proliferation, fibrosis and inflammation, but attenuated apoptosis in SV40-MES13 cells under the LG condition. Additionally, DUSP22 overexpression inactivated phosphorylated (p)-ERK, p-JNK, and p-P38 in HG-treated SV40-MES13 cells; differently, DUSP22 small interfering RNA facilitated them under the LG condition. In conclusion, DUSP22 suppresses HG-induced mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK pathway, implying its potency in DN treatment.

JNK pathway-associated phosphatase in acute ischemic stroke patients: Its correlation with T helper cells, clinical properties, and recurrence risk

Objective

JKAP modifies T‐cell immune response and inflammation, also involves in cardia‐cerebrovascular disease etiology. This study intended to explore JKAP's relation with T‐helper 1 (Th1), T‐helper 17 (Th17) cell levels, clinical properties, and recurrence‐free survival (RFS) in acute ischemic stroke (AIS) patients.

Methods

A total of 155 AIS patients were analyzed. Serum JKAP, interferon‐gamma (IFN‐γ), and interleukin‐17A (IL‐17A) were detected by ELISA; then blood Th1 and Th17 cells were quantified by flow cytometry. Besides, 30 healthy subjects were enrolled as controls to detect JKAP, Th1, and Th17 cells.

Results

JKAP level was lower (p < 0.001), Th1 cells were not differed (p = 0.068), but Th17 cells were elevated in AIS patients versus controls (p < 0.001). Meanwhile, JKAP was negatively correlated with Th1 cells (p = 0.038), Th17 cells (P<0.001), IFN‐γ (p = 0.002), and IL‐17A (p < 0.001) in AIS patients. JKAP was negatively associated with the National Institutes of Health Stroke Scale (NIHSS) score (p < 0.001), but Th17 cells (p = 0.001), IFN‐γ (p = 0.035), and IL‐17A (p = 0.008) levels were positively associated with NIHSS score. Additionally, accumulating RFS was numerically longer in patients with JKAP Quantile (Q) 4 than patients with JKAP Q1–Q3 (p = 0.068), and numerically better in patients with JKAP Q3–Q4 than patients with JKAP Q1–Q2 (p = 0.069), but without statistical significance.

Conclusion

JKAP correlates with lower Th1 and Th17 cell percentages as well as milder disease severity.

Targeting protein phosphatases for the treatment of inflammation-related diseases: From signaling to therapy

Inflammation is the common pathological basis of autoimmune diseases, metabolic diseases, malignant tumors, and other major chronic diseases. Inflammation plays an important role in tissue homeostasis. On one hand, inflammation can sense changes in the tissue environment, induce imbalance of tissue homeostasis, and cause tissue damage. On the other hand, inflammation can also initiate tissue damage repair and maintain normal tissue function by resolving injury and restoring homeostasis. These opposing functions emphasize the significance of accurate regulation of inflammatory homeostasis to ameliorate inflammation-related diseases. Potential mechanisms involve protein phosphorylation modifications by kinases and phosphatases, which have a crucial role in inflammatory homeostasis. The mechanisms by which many kinases resolve inflammation have been well reviewed, whereas a systematic summary of the functions of protein phosphatases in regulating inflammatory homeostasis is lacking. The molecular knowledge of protein phosphatases, and especially the unique biochemical traits of each family member, will be of critical importance for developing drugs that target phosphatases. Here, we provide a comprehensive summary of the structure, the "double-edged sword" function, and the extensive signaling pathways of all protein phosphatases in inflammation-related diseases, as well as their potential inhibitors or activators that can be used in therapeutic interventions in preclinical or clinical trials. We provide an integrated perspective on the current understanding of all the protein phosphatases associated with inflammation-related diseases, with the aim of facilitating the development of drugs that target protein phosphatases for the treatment of inflammation-related diseases.

Clinical value of serum JKAP in acute ischemic stroke patients

Background

Jun N‐terminal kinase pathway‐associated phosphatase (JKAP) regulates neuronal function, T helper (Th) 1/2/17 cell differentiation, and inflammatory process, but its clinical role in acute ischemic stroke (AIS) patients remains unclear. Hence, this study intended to evaluate JKAP level and its relationship with disease severity, Th1, 2, 17 secreted cytokines, adhesion molecules, and prognosis of AIS patients.

Methods

Serum JKAP of 122 AIS patients and 50 controls was detected by ELISA. For AIS patients only, Th1, 2, 17 secreted cytokines IFN‐γ, IL‐4, IL‐17; TNF‐α, ICAM‐1, and VCAM‐1 were also detected by ELISA.

Results

JKAP was decreased in AIS patients compared with controls (46.350 (interquartile range (IQR): 34.250–59.875) pg/ml vs. 84.500 (IQR: 63.175–113.275) pg/ml, p < 0.001), which could distinguish AIS patients from controls (area under curve (AUC): 0.810, 95% confidence interval (CI): 0.732–0.888). In AIS patients, JKAP negatively linked with the National Institutes of Health Stroke Scale (NIHSS) score (r_s = −0.342, p < 0.001); besides, it was positively related to IL‐4 (r_s = 0.213, p = 0.018) and negatively associated with IL‐17 (r_s = −0.270, p = 0.003) but not related to IFN‐γ (r_s = −0.146, p = 0.109). Furthermore, elevated JKAP associated with declined TNF‐α (r_s = −0.219, p = 0.015) and ICAM‐1 (r_s = −0.235, p = 0.009) but not related to VCAM‐1 (r_s = −0.156, p = 0.085). Besides, declined JKAP was linked with 2‐year recurrence (p = 0.027) and 3‐year recurrence (p = 0.010) in AIS patients; while JKAP was not related to 1‐year recurrence or death risk (both p > 0.050).

Conclusion

JKAP may sever as a candidate prognostic biomarker in AIS patients, indicating its potency for AIS management.

Dual-Specificity Phosphatases and Kidney Diseases

BACKGROUND

Dual-specificity phosphatases (DUSPs) belong to the family of protein tyrosine phosphatases, which can dephosphorylate both serine/threonine and tyrosine residues. During the past decades, DUSPs have been implicated in various physiological and pathological activities. Besides mitogen-activated protein kinases (MAPKs) as the main substrates, other protein and nonprotein substrates can also be dephosphorylated by DUSPs. Aberrant regulations of DUSPs have been found in various diseases such as cancer, neurological disorders, and kidney diseases, suggesting the involvement of DUSPs in the pathogenesis of diseases.

SUMMARY

In this review, we summarize the general characteristics of DUSPs and the research progress made in the field of kidney diseases, including diabetic nephropathy, hypertensive nephropathy, chronic kidney disease, acute kidney injury, and lupus nephritis. As the main biochemical function of DUSPs is to dephosphorylate MAPKs activity, decreased DUSPs are found in kidney disease models, whereas forced DUSPs expression reverses the disease presentation, which was proved by using transgenic or gene knockout model.

KEY MESSAGES

Mounting evidence demonstrates that DUSPs have essential physiological and pathological functions in kidney disease. Fully understanding the functions and mechanisms of DUSPs in kidney disease contributes to their clinical application in translation medicine.

Dual specificity phosphatase 22 relates to skin lesion degree and biologics history, while its longitudinal elevation during treatment reflects better outcome in psoriasis patients

Background

Dual specificity phosphatase 22 (DUSP22) plays an important role in the regulation of immune and inflammation, but its correlation with clinical features and treatment outcome in psoriasis patients is still unclear. This study was to investigate the longitudinal change of DUSP22 with time, as well as its association with disease activity and treatment response in psoriasis patients.

Methods

Totally, 120 psoriasis patients, 50 patients with other skin inflammations as disease controls (DCs), and 50 health controls (HCs) were recruited. Serum samples were collected from psoriasis patients at baseline, month (M)1, M3, and M6 after initiation of etanercept‐based treatment as well as from DCs and HCs after enrollment to assess DUSP22 level by enzyme‐linked immunosorbent assay.

Results

DUSP22 was lower in psoriasis patients than in HCs and DCs (both p < 0.001). Besides, in psoriasis patients, DUSP22 was associated with lower psoriasis area severity index (PASI) score (p = 0.001) and systemic biological treatment history (p = 0.023), but not with other demographics, disease characteristics, or treatment history (all p>0.05). In addition, DUSP22 was increased with time (p < 0.001) in total patients. Moreover, DUSP22 at M3 (p = 0.004) and M6 (p < 0.001) was higher in response patients than in non‐response patients evaluated by PASI 75. Additionally, DUSP22 at M3 (p < 0.001) and M6 (p = 0.003) was also increased in response patients compared with non‐response patients evaluated by PASI 90.

Conclusion

DUSP22 decreases and negatively correlates with disease activity, while its longitudinal elevation with time reflects satisfactory treatment response in psoriasis patients.

Circulating JNK pathway-associated phosphatase: A novel biomarker correlates with Th17 cells, acute exacerbation risk, and severity in chronic obstructive pulmonary disease patients

Background

JNK pathway‐associated phosphatase (JKAP) involves in the regulation of inflammation, immunity, and lung injury. The current study aimed to investigate correlation of JKAP with Th1, Th17 cells, acute exacerbation risk, and disease severity in chronic obstructive pulmonary disease (COPD) patients.

Methods

Totally, 45 stable COPD (SCOPD) patients, 45 acute exacerbation COPD (AECOPD) patients, and 45 controls were enrolled. Serum was collected for JKAP, interferon‐gamma (IFN‐γ) (Th1 cytokine), and interleukin 17 (IL‐17) (Th17 cytokine) detection. Besides, peripheral blood mononuclear cell from COPD patients was collected for evaluating Th1 and Th17 cells.

Results

JKAP was highest in controls followed by SCOPD patients and lowest in AECOPD patients (median: 105.673 vs. 75.374 vs. 41.807 pg/ml, p < 0.001). Meanwhile, receiver operating characteristic (ROC) curves revealed that JKAP differentiated the AECOPD patients from the controls (area under curve (AUC): 0.910 (95% confidence interval (CI): 0.849–0.970)) and AECOPD patients from SCOPD patients (AUC: 0.726 (95% CI: 0.622–0.830)). Moreover, JKAP positively correlated with FEV₁ (%predicted) in AECOPD patients (r = 0.347 p = 0.019). Additionally, JKAP was negatively correlated with the GOLD stage in AECOPD patients (r = −0.344, p = 0.021) and SCOPD patients (r = −0.357, p = 0.016). Whereas, JKAP was not associated with other clinical features (all p > 0.05). Besides, JKAP was negatively linked with Th17 cells (r = −0.378, p = 0.010), IFN‐γ (r = −0.358, p = 0.016), IL‐17 (r = −0.414, p = 0.005) in AECOPD patients and Th17 cells (r = −0.342, p = 0.022), IL‐17 (r = −0.299, p = 0.046) in SCOPD patients.

Conclusion

Downregulated JKAP correlates with Th17 cells, higher acute exacerbation risk, and severity in COPD patients, indicating its underlying potency as a biomarker for COPD.

Evaluation of molecular apoptosis signaling pathways and its correlation with EBV viral load in SLE patients using systems biology approach

BACKGROUND

Considerable evidence supports that SLE could be related to apoptotic cells and EBV infection.

OBJECTIVE

The aim of this study was to identify the transcriptional signature of EBV infection in SLE patients for survey of the molecular apoptosis signaling pathways.

METHODS

The PBMCs gene expression profiles of healthy control and SLE patients were obtained from GEO. Functional annotation and signaling pathway enrichment were carried out using DAVID, KEGG. To validate bioinformatics analysis the changes in genes expression of some of obtained genes, Real time PCR was performed on PBMCs from 28 SLE patients and 18 controls.

RESULTS

We found that mean viral load was 6013 ± 390.1 copy/μg DNA from PBMCs in all patients. QRT-PCR results showed that the expression of the DUSP1 and LAMP3 genes which had most changes in the logFC among 4 candidate genes, increased significantly in comparison with control. The consistent expression of LMP2 as viral latency gene involve in apoptosis signaling pathways was detected in SLE patients with EBV viral load and some controls.

CONCLUSIONS

The study indicated that some cellular genes may have an important role in pathogenesis of SLE through apoptosis signaling pathways. Beside, EBV infection as an environmental risk factor for SLE may affect the dysfunction of apoptosis.

Measurement of synovium and serum dual specificity phosphatase 22 level: Their inter-correlation and potency as biomarkers in rheumatoid arthritis

Background

Dual specificity phosphatase 22 (DUSP22), also named as Jun N‐terminal kinase pathway associated phosphatase recently, is reported to be closely engaged in immune and inflammation regulation. This study aimed to investigate the interaction between synovium DUSP22 and serum DUSP22 levels and to explore their correlation with rheumatoid arthritis (RA) risk, inflammation, and disease activity.

Methods

Synovium and serum samples from 42 RA patients with knee involvement underwent arthroscopy, and 20 knee trauma patients were collected. Besides, serum samples from 40 healthy controls were also obtained. Synovium DUSP22 expression was detected by reverse transcription quantitative polymerase chain reaction, while serum DUSP22 level was detected by enzyme‐linked immunosorbent assay.

Results

Synovium DUSP22 level was greatly decreased in RA patients compared to trauma controls (p < 0.001), and it was negatively correlated with tender joint count (TJC) (r = −0.318, p = 0.040), C‐reactive protein (CRP) (r = −0.330, p = 0.033), and Lysholm score (r = −0.423, p = 0.005) in RA patients. Serum DUSP22 level was lowest in RA patients, followed by trauma controls, then highest in healthy controls (p < 0.001). Serum DUSP22 level was negatively associated with TJC (r = −0.438, p = 0.004), swollen joint count (SJC) (r = −0.372, p = 0.015), CRP (r = −0.391, p = 0.011), and disease activity score in 28 joints (DAS28_ESR) score (r = −0.406, p = 0.008), and it increased after treatment (p = 0.001) in RA patients. In addition, serum DUSP22 level positively related to synovium DUSP22 level in RA patients (r = 0.394, p = 0.010).

Conclusion

Synovium and serum DUSP22 are intercorrelated and insufficiently expressed in RA patients; meanwhile, their deficiency correlates with increased systemic inflammation, disease activity, and joint dysfunction.

JKAP, Th1 cells, and Th17 cells are dysregulated and inter-correlated, among them JKAP and Th17 cells relate to cognitive impairment progression in Alzheimer's disease patients

BACKGROUND

JNK pathway-associated phosphatase (JKAP) is engaged in Alzheimer's disease (AD) pathology via regulating immune response, cluster of differentiation 4 positive (CD4⁺) T cell differentiation, inflammation, and phosphorylated tau (p-tau). This study aimed to investigate its clinical value serving as a biomarker for AD.

METHODS

Fifty AD patients, 50 Parkinson's disease (PD) patients, and 50 controls (patients with non-degenerative neurological diseases with normal cognition) were enrolled. Their β-protein 42 (Aβ42), total tau (t-tau), p-tau, and Mini-Mental State Examination (MMSE) scale were assessed. Furthermore, JKAP in serum and T-help type 1 (Th1) and T-help type 17 (Th17) cells in CD4⁺ T cells were measured.

RESULTS

JKAP level was lower, while Th17 cell proportion (but not Th1 cell proportion) was higher in AD patients compared with PD patients and controls (all P < 0.01). Besides, JKAP level negatively correlated with both Th1 (r =  - 0.306, P = 0.030) and Th17 (r =  - 0.380, P = 0.006) cell proportions in AD patients but not PD patients and controls. Furthermore, in AD patients, JKAP positively correlated with Aβ42 (r = 0.307, P = 0.030) and MMSE score (r = 0.350, P = 0.013) while negatively correlated with p-tau (r =  - 0.280, P = 0.048); Th17 cell proportion negatively associated with Aβ42 (r =  - 0.281, P = 0.048) and MMSE score (r =  - 0.366, P = 0.009). Notably, JKAP was negatively related to 1-year (r =  - 0.297, P = 0.038) and 2-year MMSE decline (r =  - 0.304, P = 0.048); Th17 cell proportion was positively linked with 1-year (r = 0.392; P = 0.008), 2-year (r = 0.482, P = 0.001), and 3-year (r = 0.365, P = 0.013) MMSE decline.

CONCLUSION

JKAP, Th1 cells, and Th17 cells are dysregulated and inter-correlated; among them, JKAP and Th17 cells relate to cognitive impairment progression in AD patients.

ALK-Negative Anaplastic Large Cell Lymphoma: Current Concepts and Molecular Pathogenesis of a Heterogeneous Group of Large T-Cell Lymphomas

Simple Summary

ALK- anaplastic large cell lymphoma (ALK- ALCL) is a rare subtype of CD30+ large T-cell lymphoma that typically affects older adults and has a poor prognosis. Recognition of its histopathologic spectrum, subtypes, and of other tumors that can resemble ALK- ALCL is crucial to avoid making a wrong diagnosis that could result in inappropriate treatment for a patient. In recent years, several important studies have identified recurrent molecular alterations that have shed light on the pathogenesis of this lymphoma. However, on the other hand, putting all this vast information together into a concise form has become challenging. In this review, we present not only a more detailed view of the histopathologic findings of ALK- ALCL but also, we attempt to provide a more simplified perspective of the relevant genetic and molecular alterations of this type of lymphoma, that in our opinion, is not available to date.

Abstract

Anaplastic large cell lymphoma (ALCL) is a subtype of CD30+ large T-cell lymphoma (TCL) that comprises ~2% of all adult non-Hodgkin lymphomas. Based on the presence/absence of the rearrangement and expression of anaplastic lymphoma kinase (ALK), ALCL is divided into ALK+ and ALK-, and both differ clinically and prognostically. This review focuses on the historical points, clinical features, histopathology, differential diagnosis, and relevant cytogenetic and molecular alterations of ALK- ALCL and its subtypes: systemic, primary cutaneous (pc-ALCL), and breast implant-associated (BIA-ALCL). Recent studies have identified recurrent genetic alterations in this TCL. In systemic ALK- ALCL, rearrangements in DUSP22 and TP63 are detected in 30% and 8% of cases, respectively, while the remaining cases are negative for these rearrangements. A similar distribution of these rearrangements is seen in pc-ALCL, whereas none have been detected in BIA-ALCL. Additionally, systemic ALK- ALCL—apart from DUSP22-rearranged cases—harbors JAK1 and/or STAT3 mutations that result in the activation of the JAK/STAT signaling pathway. The JAK1/3 and STAT3 mutations have also been identified in BIA-ALCL but not in pc-ALCL. Although the pathogenesis of these alterations is not fully understood, most of them have prognostic value and open the door to the use of potential targeted therapies for this subtype of TCL.

JKAP serves as a potential biomarker for the evaluation of inflammatory condition, disease activity, and treatment response to TNF inhibitor in ankylosing spondylitis patients

OBJECTIVE

This study aimed to evaluate the value of JKAP as a biomarker in estimating treatment response to TNF inhibitor in AS patients.

METHODS

Totally, 63 AS patents who planned to receive adalimumab (TNF inhibitor) treatment were enrolled. Baseline JKAP level was determined in serum samples. All patients received 40 mg adalimumab every two weeks for 12 weeks. At W2, W4, W8, and W12, ASAS40 response rates were evaluated.

RESULTS

JKAP was negatively correlated with CRP (P = 0.032), BASDAI score (P = 0.021), BASFI score (P = 0.045), ASDASCRP score (P = 0.038), TNF-α (P = 0.031), IL-6 (P = 0.025) and IL-17A (P = 0.022). The ASAS40 response rates were 17.5%, 31.7%, 44.4% and 55.5% at W2, W4, W8 and W12, respectively. Baseline JKAP level was lower in patients with ASAS40 response than those without ASAS40 response (25.8 (13.2-42.7) pg/mL vs. 47.3 (26.7-71.2) pg/mL, P = 0.003). Multivariate logistic regression disclosed that JKAP level (P = 0.049) and CRP level (P = 0.014) independently correlated with ASAS40 response; further analyses disclosed that they exhibited acceptable to good ability in distinguishing patients with ASAS40 response from those without ASAS40 response.

CONCLUSION

JKAP serves as a potential biomarker for evaluation of inflammatory condition, disease activity, especially for assessing treatment response to TNF inhibitor in AS patients.

JKAP relates to disease risk, severity, and Th1 and Th17 differentiation in Parkinson's disease

Objective

JNK pathway‐associated phosphatase (JKAP) is previously reported to regulate immune/inflammatory process via T‐cell signaling, and closely involves in neurological diseases, while its implication in Parkinson's disease (PD) is unknown. Therefore, this study aimed to investigate the correlation of JKAP with Th1/Th2/Th17 cells and their clinical roles in PD patients, and then further explore the effect of JKAP on regulating CD4⁺ T‐cell differentiation in PD.

Methods

Totally 50 PD patients and 50 age‐/gender‐matched controls were enrolled. Their blood samples were collected and proposed to ELISA and flow cytometry assays for JKAP, Th1, Th2, and Th17 measurements. In vitro, CD4⁺ T cells were isolated from PD patients then transfected with JKAP overexpression and knockdown Lentivirus, followed by detection of markers (CD25⁺ cell proportion, CD69⁺ cell proportion, IFN‐γ, IL10, and IL17).

Results

JKAP was downregulated in PD patients compared to controls, which also showed good potency to discriminate them. Besides, JKAP negatively correlated with Th1 and Th17 cell proportions, but did not associate with Th2 cell proportion in PD patients; Interestingly, JKAP did not correlated with Th1, Th2, or Th17 cell proportions in controls. Furthermore, JKAP correlated with some parts of unified Parkinson’s Disease Rating Scale (UPDRS) and Mini‐Mental State Examination (MMSE) score. In vitro, JKAP overexpression repressed CD4⁺ T‐cell activation and its differentiation into Th1 and Th17 cells in PD, while JKAP knockdown appeared opposite effect.

Interpretation

JKAP associates with disease risk and severity, correlates with Th1 and Th17 cells, and regulates CD4⁺ T‐cell activation/differentiation in PD.

Longitudinal monitor of Jun N-terminal kinase pathway associated phosphatase reflects clinical efficacy to triple conventional disease-modifying anti-rheumatic drugs treatment in rheumatoid arthritis patients

OBJECTIVE

This study aimed to investigate the correlation of Jun N-terminal kinase pathway associated phosphatase (JKAP) with inflammation, disease activity, and clinical efficacy to triple conventional disease-modifying anti-rheumatic drugs (cDMARDs) in rheumatoid arthritis (RA) patients.

METHODS

A total of 119 active RA patients about to receive triple cDMARDs treatment were enrolled. Serum JKAP was detected by enzyme-linked immunosorbent assay at week0, week6, week12, and week24 (W24). According to clinical response status or remission status at W24, RA patients were classified as response patients and non-response patients, or remission patients and non-remission patients, respectively.

RESULTS

JKAP was negatively correlated with erythrocyte sedimentation rate (ESR), C-reactive protein, and 28-joints disease activity score based on ESR (DAS28 score (ESR)), while JKAP was not correlated with disease duration, tender joint count, swollen joint count, health assessment questionnaire for rheumatoid arthritis or treatment history. Furthermore, during 24-week triple cDMARDs treatment, JKAP was increased overtime. Subgroup analyses showed that JKAP displayed a rising trend in response patients, remission patients, non-remission patients but not non-response patients, meanwhile its increment was more obvious in remission patients versus non-remission patients. Additionally, JKAP at W24 was higher in response patients compared with non-response patients, and JKAP at W12 and W24 was higher in remission patients compared with non-remission patients.

CONCLUSION

Longitudinal monitor of JKAP might reflect clinical efficacy to the treatment of triple cDMARDs, which could improve outcomes in RA patients.

ECP Overexpression in T Cells and Exosomes Induces IFN-γ Production and Tissue Inflammation

Objective

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Serum‐derived exosomes are increased in SLE patients and are correlated with disease severity. This study was undertaken to investigate whether T cell–derived exosomal proteins play a role in SLE pathogenesis.

Methods

We characterized proteins in T cell–derived exosomes from SLE patients and healthy controls by MACSPlex exosome analysis and proteomics. To study the potential pathogenic functions of the exosomal protein identified, we generated and characterized T cell–specific transgenic mice that overexpressed that protein in T cells.

Results

We identified eosinophil cationic protein (ECP, also called human RNase III) as overexpressed in SLE T cell–derived exosomes. T cell–specific ECP–transgenic mice (n = 5 per group) displayed early induction of serum interferon‐γ (IFNγ) levels (P = 0.062) and inflammation of multiple tissue types. Older T cell–specific ECP–transgenic mice (n = 3 per group) also displayed an increase in follicular helper T cell and plasma B cell numbers, and in autoantibody levels (P < 0.01). Single‐cell RNA sequencing showed the induction of IFNγ messenger RNA (P = 2.2 × 10^‐13) and inflammatory pathways in ECP‐transgenic mouse T cells. Notably, adoptively transferred ECP‐containing exosomes stimulated serum autoantibody levels (P < 0.01) and tissue IFNγ levels in the recipient mice (n = 3 per group). The transferred exosomes infiltrated into multiple tissues of the recipient mice, resulting in hepatitis, nephritis, and arthritis.

Conclusion

Our findings indicate that ECP overexpression in T cells or T cell–derived exosomes may be a biomarker and pathogenic factor for nephritis, hepatitis, and arthritis associated with SLE.

The MAPK dual specific phosphatase (DUSP) proteins: A versatile wrestler in T cell functionality

The functional state of T cells is diverse and under dynamic control for adapting to the changes of microenvironment. Reversible protein phosphorylation represents an important post-translational modification that not only involves in the immediate early response of T cells, but also affects their functionality in the long run. Perturbation of global phosphorylation profile and/or phosphorylation of specific signaling nodes result in aberrant T cell activity. Dual specific phosphatases (DUSPs), which target MAPKs and beyond, have increasingly been emerged as a versatile regulator in T cell biology. Herein in this mini review, we sought to summarize and discuss the impact of DUSP proteins on the regulation of effector T cell activity, T cell polarization, regulatory T cell development and T cell senescence/exhaustion. Given the distinctive engagement of each DUSP member under various disease settings such as chronic infection, autoimmune disorders, cancer and age-related diseases, DUSP proteins likely hold the promise to become a druggable target other than the existing therapeutics that are predominantly by manipulating protein kinase activity.

DNA Methylation Analysis to Unravel Altered Genetic Pathways Underlying Early Onset and Late Onset Neonatal Sepsis. A Pilot Study

Background: Neonatal sepsis is a systemic condition widely affecting preterm infants and characterized by pro-inflammatory and anti-inflammatory responses. However, its pathophysiology is not yet fully understood. Epigenetics regulates the immune system, and its alteration leads to the impaired immune response underlying sepsis. DNA methylation may contribute to sepsis-induced immunosuppression which, if persistent, will cause long-term adverse effects in neonates.

Objective: To analyze the methylome of preterm infants in order to determine whether there are DNA methylation marks that may shed light on the pathophysiology of neonatal sepsis.

Design: Prospective observational cohort study performed in the neonatal intensive care unit (NICU) of a tertiary care center.

Patients: Eligible infants were premature ≤32 weeks admitted to the NICU with clinical suspicion of sepsis. The methylome analysis was performed in DNA from blood using Infinium Human Methylation EPIC microarrays to uncover methylation marks.

Results: Methylation differential analysis revealed an alteration of methylation levels in genomic regions involved in inflammatory pathways which participate in both the innate and the adaptive immune response. Moreover, differences between early and late onset sepsis as compared to normal controls were assessed.

Conclusions: DNA methylation marks can serve as a biomarker for neonatal sepsis and even contribute to differentiating between early and late onset sepsis.

JNK pathway-associated phosphatase associates with rheumatoid arthritis risk, disease activity, and its longitudinal elevation relates to etanercept treatment response

Background

This study aimed to investigate the relationship of serum JNK pathway‐associated phosphatase (JKAP) expression with rheumatoid arthritis (RA) risk and clinical features, also to explore the longitudinal change of JKAP during etanercept treatment and its relationship with etanercept treatment response in RA patients.

Methods

A total of 87 RA patients and 44 healthy controls (HCs) were enrolled; then, their JKAP expression in serum was determined by enzyme‐linked immunosorbent assay (ELISA). Among 87 RA patients, 42 cases further received the 24‐week etanercept treatment; then, their JKAP level in serum (detected by ELISA) and clinical response (evaluated by disease activity score in 28 joints (DAS28) score) were evaluated at week 4 (W4), week 12 (W12), and week 24 (W24) after initiation of etanercept treatment.

Results

JKAP expression was decreased in RA patients compared to HCs, which disclosed a good predictive value for RA risk. JKAP expression was negatively associated with tender joint count, swollen joint count, erythrocyte sedimentation rate, C‐reactive protein, and DAS28 in RA patients, respectively. For RA patients who received 24‐week etanercept treatment, their clinical response rate was 0.0%, 33.3%, 50.0%, and 69% at W0, W4, W12, and W24, respectively. Importantly, JKAP was gradually increased during etanercept treatment, whose longitudinal elevation positively related to etanercept treatment response in RA patients.

Conclusion

Circulating JKAP links with decreased RA risk and mild disease activity, whose longitudinal elevation positively relates to etanercept treatment response.

JNK Pathway-Associated Phosphatase as a Serum Marker for Disease Activity and Treatment Outcome of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is a heterogeneous autoimmune disease characterized by arthritis of unknown etiology. JNK pathway-associated phosphatase (JKAP) is reported to be a negative regulator of T-cell activation, but its clinical role in JIA is unknown. This study aimed to investigate the correlation of JKAP with disease activity and treatment response to a tumor necrosis factor (TNF) inhibitor, etanercept (ETN), in JIA patients. Totally, 104 JIA patients (6.9 ± 2.7 years old) and 100 age- and sex-matched healthy controls (HCs) (7.2 ± 2.4 years old) were enrolled, and their serum samples were collected for measuring JKAP by enzyme-linked immunoassay. In JIA patients, after 24-week ETN treatment, clinical response was assessed based on the American College of Rheumatology pediatric criteria (ACRpedi) 50 criteria. Results showed that JKAP levels were significantly lower in JIA patients compared with HCs, and of good value in differentiating JIA patients from HCs. Among JIA patients, higher JKAP levels were associated with lower disease activity indexes, including C-reactive protein, number of joints with active arthritis, physician's global assessment of disease activity, and the present history of disease-modifying antirheumatic drugs; higher baseline JKAP levels were correlated with worse ACRpedi 50 response to ETN at week 24, and was also an independent predictive factor for worse ACRpedi 50 response to ETN. Thus, it may be inappropriate to use ETN for JIA patients with higher JKAP levels. In conclusion, serum JKAP is a potential biomarker for JIA activity and treatment response to a TNF inhibitor.

Reduced JKAP correlates with advanced disease features, inflammation, as well as increased exacerbation risk and severity in asthmatic children

BACKGROUND

This study aimed to investigate the correlation of JNK pathway-associated phosphatase (JKAP) with clinical features, inflammation, exacerbation risk, and severity in asthmatic children.

METHODS

Asthmatic exacerbation children (N = 90), asthmatic remission children (N = 90), and healthy controls (N = 90) were enrolled in this case-control study, whose venous blood samples were collected after enrollment for routine blood test, JKAP, and inflammatory cytokines detection by enzyme-linked immune sorbent assay. The clinical features included demographic data, family history of asthma, and pulmonary ventilation function.

RESULTS

JKAP level was the lowest in asthmatic exacerbation children, followed by asthmatic remission children and healthy controls. ROC curve revealed good ability of JKAP in distinguishing three groups from each other, especially in telling asthmatic exacerbation children from healthy controls (AUC: 0.926; 95%CI: 0.887-0.965). In addition, JKAP was negatively correlated with eosinophil count, immunoglobulin E (IgE), tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-17 (IL-17), positively correlated with forced expiratory volume in 1 sec/forced vital capacity (FEV₁/FVC) and FEV₁ (%predicted) in asthmatic exacerbation children. Whereas in asthmatic remission children, JKAP was negatively correlated with eosinophil count, TNF-α, IL-1β, IL-6, and IL-17 and positively correlated with FEV₁ (%predicted), but not with IgE or FEV₁/FVC. In healthy controls, the correlation of JKAP with clinical features and inflammatory cytokines was non-obvious. For exacerbation severity, JKAP was the highest in mild exacerbation children, followed by moderate exacerbation children, and severe exacerbation children.

CONCLUSION

JKAP serves as a potential biomarker for asthmatic susceptibility, inflammation, exacerbation risk, and severity in children.

The correlation between Jun N-terminal kinase pathway-associated phosphatase and Th1 cell or Th17 cell in sepsis and their potential roles in clinical sepsis management

Background

We aimed to investigate the association between Jun N-terminal kinase (JNK) pathway-associated phosphatase (JKAP) and T helper type 1 (Th1) cell or Th17 cell, and their clinical values in sepsis patients.

Methods

Totally 125 sepsis patients and 100 healthy subjects as controls were included. Peripheral blood was extracted from each sepsis patient and each control, then serum and peripheral blood mononuclear cell (PBMC) were separated. JKAP and inflammatory cytokines were detected in serum by ELISA; Th1 cell or Th17 cell proportion was detected in PBMC using flow cytometry.

Results

JKAP level was downregulated while Th1 and Th17 cell proportions were upregulated in sepsis patients compared with controls. JKAP level negatively correlated with Th1 cell proportion in sepsis patients and controls, while was only negatively associated with Th17 cell proportion in sepsis patients but not in controls. In sepsis patients, JKAP level negatively associated with TNF-α, IL-1β, and IL-17 expressions. Meanwhile, JKAP level negatively but Th17 cell proportion positively correlated with acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) scores; however, Th1 cell proportion only positively associated with APACHE II score but not SOFA score. Additionally, JKAP level was reduced, while Th1 and Th17 cell proportions were increased in septic deaths compared with survivors. Multivariate logistic regression model disclosed that JKAP level and Th17 cell proportion independently predicted 28-day mortality.

Conclusion

Blood JKAP correlates with decreased Th1 and Th17 cells, also associates with reduced inflammatory cytokines, disease severity, and favorable outcome in sepsis patients.

Structural Insights into the Active Site Formation of DUSP22 in N-loop-containing Protein Tyrosine Phosphatases

Cysteine-based protein tyrosine phosphatases (Cys-based PTPs) perform dephosphorylation to regulate signaling pathways in cellular responses. The hydrogen bonding network in their active site plays an important conformational role and supports the phosphatase activity. Nearly half of dual-specificity phosphatases (DUSPs) use three conserved residues, including aspartate in the D-loop, serine in the P-loop, and asparagine in the N-loop, to form the hydrogen bonding network, the D-, P-, N-triloop interaction (DPN-triloop interaction). In this study, DUSP22 is used to investigate the importance of the DPN-triloop interaction in active site formation. Alanine mutations and somatic mutations of the conserved residues, D57, S93, and N128 substantially decrease catalytic efficiency (k_cat/K_M) by more than 10²-fold. Structural studies by NMR and crystallography reveal that each residue can perturb the three loops and induce conformational changes, indicating that the hydrogen bonding network aligns the residues in the correct positions for substrate interaction and catalysis. Studying the DPN-triloop interaction reveals the mechanism maintaining phosphatase activity in N-loop-containing PTPs and provides a foundation for further investigation of active site formation in different members of this protein class.

Genome-Wide Meta-Analysis Identifies Three Novel Susceptibility Loci and Reveals Ethnic Heterogeneity of Genetic Susceptibility for IgA Nephropathy

BACKGROUND

Eighteen known susceptibility loci for IgAN account for only a small proportion of IgAN risk.

METHODS

Genome-wide meta-analysis was performed in 2628 patients and 11,563 controls of Chinese ancestry, and a replication analysis was conducted in 6879 patients and 9019 controls of Chinese descent and 1039 patients and 1289 controls of European ancestry. The data were used to assess the association of susceptibility loci with clinical phenotypes for IgAN, and to investigate genetic heterogeneity of IgAN susceptibility between the two populations. Imputation-based analysis of the MHC/HLA region extended the scrutiny.

RESULTS

Identification of three novel loci (rs6427389 on 1q23.1 [P=8.18×10^-9, OR=1.132], rs6942325 on 6p25.3 [P=1.62×10^-11, OR=1.165], and rs2240335 on 1p36.13 [P=5.10×10^-9, OR=1.114]), implicates FCRL3, DUSP22.IRF4, and PADI4 as susceptibility genes for IgAN. Rs2240335 is associated with the expression level of PADI4, and rs6427389 is in high linkage disequilibrium with rs11264799, which showed a strong expression quantitative trail loci effect on FCRL3. Of the 24 confirmed risk SNPs, six showed significant heterogeneity of genetic effects and DEFA showed clear evidence of allelic heterogeneity between the populations. Imputation-based analysis of the MHC region revealed significant associations at three HLA polymorphisms (HLA allele DPB1*02, AA_DRB1_140_32657458_T, and AA_DQA1_34_32717152) and two SNPs (rs9275464 and rs2295119).

CONCLUSIONS

A meta-analysis of GWAS data revealed three novel genetic risk loci for IgAN, and three HLA polymorphisms and two SNPs within the MHC region, and demonstrated the genetic heterogeneity of seven loci out of 24 confirmed risk SNPs.  These variants may explain susceptibility differences between Chinese and European populations.

DUSP11 Attenuates Lipopolysaccharide-Induced Macrophage Activation by Targeting TAK1

Dual-specificity phosphatase 11 (DUSP11, also named as PIR1) is a member of the atypical DUSP protein tyrosine phosphatase family. DUSP11 is only known to be an RNA phosphatase that regulates noncoding RNA stability. To date, the role of DUSP11 in immune cell signaling and immune responses remains unknown. In this study, we generated and characterized the immune cell functions of DUSP11-deficient mice. We identified TGF-β-activated kinase 1 (TAK1) as a DUSP11-targeted protein. DUSP11 interacted directly with TAK1, and the DUSP11-TAK1 interaction was enhanced by LPS stimulation in bone marrow-derived macrophages. DUSP11 deficiency enhanced the LPS-induced TAK1 phosphorylation and cytokine production in bone marrow-derived macrophages. Furthermore, DUSP11-deficient mice were more susceptible to LPS-induced endotoxic shock. The LPS-induced serum levels of IL-1β, TNF-α, and IL-6 were significantly elevated in DUSP11-deficient mice compared with those of wild-type mice. The data indicate that DUSP11 inhibits LPS-induced macrophage activation by targeting TAK1.

MAP4K Family Kinases and DUSP Family Phosphatases in T-Cell Signaling and Systemic Lupus Erythematosus

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE), which is a severe autoimmune disease. In the past 60 years, only one new therapeutic agent with limited efficacy has been approved for SLE treatment; therefore, the development of early diagnostic biomarkers and therapeutic targets for SLE is desirable. Mitogen-activated protein kinase kinase kinase kinases (MAP4Ks) and dual-specificity phosphatases (DUSPs) are regulators of MAP kinases. Several MAP4Ks and DUSPs are involved in T-cell signaling and autoimmune responses. HPK1 (MAP4K1), DUSP22 (JKAP), and DUSP14 are negative regulators of T-cell activation. Consistently, HPK1 and DUSP22 are downregulated in the T cells of human SLE patients. In contrast, MAP4K3 (GLK) is a positive regulator of T-cell signaling and T-cell-mediated immune responses. MAP4K3 overexpression-induced RORγt–AhR complex specifically controls interleukin 17A (IL-17A) production in T cells, leading to autoimmune responses. Consistently, MAP4K3 and the RORγt–AhR complex are overexpressed in the T cells of human SLE patients, as are DUSP4 and DUSP23. In addition, DUSPs are also involved in either human autoimmune diseases (DUSP2, DUSP7, DUSP10, and DUSP12) or T-cell activation (DUSP1, DUSP5, and DUSP14). In this review, we summarize the MAP4Ks and DUSPs that are potential biomarkers and/or therapeutic targets for SLE.

Circulating JNK pathway-associated phosphatase level correlates with decreased risk, activity, inflammation level and reduced clinical response to tumor necrosis factor-α inhibitor in Crohn disease patients

OBJECTIVE

This study aimed to investigate the correlation of serum Jun-amino-terminal kinase (JNK) pathway-associated phosphatase (JKAP) level with disease risk, severity, inflammation, and treatment response to tumor necrosis factor (TNF)-α inhibitor in Crohn disease (CD) patients.

METHOD

Ninety-six active CD patients and 90 healthy controls (HCs) were consecutively enrolled. Serum JKAP level of participants was determined via enzyme-linked immunosorbent assay (ELISA). In CD patients, C-reactive protein (CRP), erythrocyte sedimentation rate, Crohn disease activity index (CDAI), and inflammatory cytokine levels (determined by ELISA) were recorded. All CD patients underwent infliximab (IFX) treatment for 12 weeks, then treatment response (defined as decrement of CDAI ≥70) was assessed at week 12 (W12).

RESULTS

Serum JKAP level in CD patients was lower compared to HCs, and it disclosed a good predictive value for decreased CD risk; meanwhile, it was negatively correlated with CRP level, CDAI score, TNF-α, interleukin (IL)-6, and IL-17 levels in CD patients. Sixty-eight (70.8%) patients achieved treatment response to IFX at W12, and JKAP level was increased at W12 compared to baseline. Interestingly, baseline JKAP level in response patients was decreased compared to nonresponse patients, and it exhibited a good predictive value for decreased treatment response to IFX, multivariate logistic regression revealed that JKAP was an independent factor for predicting reduced IFX response.

CONCLUSION

Circulating JKAP expression correlates with decreased disease risk, activity, and inflammation level, and it could be served as a novel biomarker for predicting reduced clinical response to TNF-α inhibitor in CD patients.

AhR-ROR-γt complex is a therapeutic target for MAP4K3/GLKhighIL-17Ahigh subpopulation of systemic lupus erythematosus

The cytokine IL-17A plays critical roles in the pathogenesis of autoimmune diseases. The frequencies of MAP kinase kinase kinase kinase 3 [also named germinal center kinase-like kinase (GLK)]-overexpressing T cells are correlated with disease severity of systemic lupus erythematosus (SLE). T-cell-specific GLK-transgenic mice develop spontaneous autoimmune responses through IL-17A. GLK signaling selectively stimulates IL-17A production in murine T cells through inducing aryl hydrocarbon receptor (AhR)-retinoic acid receptor-related orphan nuclear receptor-γt (ROR-γt) complex formation. Here, we investigated whether GLK-induced AhR-ROR-γt complex in T cells is a therapeutic target for human SLE. The population of GLK⁺IL-17A⁺ T cells was enhanced in the peripheral blood from patients with SLE compared with that of healthy controls using flow cytometry. The receiver operating characteristic curve analysis showed that increased GLK⁺IL-17A⁺ T-cell population in peripheral blood reflected an active stage of SLE. In addition, peripheral blood T cells from patients with SLE displayed induction of ROR-γt phosphorylation and the AhR-ROR-γt (and AhR-phosphorylated ROR-γt) complex. Moreover, we identified a small-molecule inhibitor, verteporfin, that inhibited GLK kinase activity and AhR-ROR-γt interaction. The small-molecule inhibitor verteporfin suppressed the disease severity in autoimmune mouse models and IL-17A production in T cells from patients with SLE. Collectively, the GLK-induced AhR-ROR-γt (and AhR-phosphorylated ROR-γt) complex is a therapeutic target for the GLK^highIL-17A^high subpopulation of human patients with SLE.-Chuang, H.-C., Chen, Y.-M., Chen, M.-H., Hung, W.-T., Yang, H.-Y., Tseng, Y.-H., Tan, T.-H. AhR-ROR-γt complex is a therapeutic target for MAP4K3/GLK^highIL-17A^high subpopulation of systemic lupus erythematosus.

Regulation of CD4+ T Cell Signaling and Immunological Synapse by Protein Tyrosine Phosphatases: Molecular Mechanisms in Autoimmunity

T cell activation and effector function is mediated by the formation of a long-lasting interaction established between T cells and antigen-presenting cells (APCs) called immunological synapse (IS). During T cell activation, different signaling molecules as well as the cytoskeleton and the endosomal compartment are polarized to the IS. This molecular dynamics is tightly regulated by phosphorylation networks, which are controlled by protein tyrosine phosphatases (PTPs). While some PTPs are known to be important regulators of adhesion, ligand discrimination or the stimulation threshold, there is still little information about the regulatory role of PTPs in cytoskeleton rearrangements and endosomal compartment dynamics. Besides, spatial and temporal regulation of PTPs and substrates at the IS is only barely known. Consistent with an important role of PTPs in T cell activation, multiple mutations as well as altered expression levels or dynamic behaviors have been associated with autoimmune diseases. However, the precise mechanism for the regulation of T cell activation and effector function by PTPs in health and autoimmunity is not fully understood. Herein, we review the current knowledge about the regulatory role of PTPs in CD4⁺ T cell activation, IS assembly and effector function. The potential molecular mechanisms mediating the action of these enzymes in autoimmune disorders are discussed.

Downregulation of JKAP is correlated with elevated disease risk, advanced disease severity, higher inflammation, and poor survival in sepsis

OBJECTIVE

This study aimed to explore the association of JKAP with sepsis risk and investigate its correlation with disease severity, inflammatory cytokines, and survival in sepsis patients.

METHODS

A hundred and one sepsis patients along with 100 healthy controls were enrolled, and their blood serum samples were collected for JKAP and inflammatory cytokines measurement by enzyme-linked immunoassay. The difference in serum JKAP between sepsis patients and healthy controls was determined. Among sepsis patients, the correlation of JKAP with disease severity, laboratory indexes, inflammatory cytokines, 28-day mortality, and accumulating survival was analyzed.

RESULTS

JNK pathway-associated phosphatase level was decreased in sepsis patients compared with healthy controls and presented with good value in predicting decreased sepsis risk (AUC = 0.896 [95% CI: 0.851-0.941]). And its low expression was associated with advanced disease severity (APACHE II score and SOFA score) and systemic inflammation (CRP, PCT, TNF-α, IL-1β, IL-6, and IL-17) in sepsis patients. Additionally, JKAP level was decreased in deaths compared with survivors and had good value in distinguishing deaths from survivors (AUC = 0.742 [95% CI: 0.636-0.849]). Further, Kaplan-Meier curve analysis disclosed that JKAP high expression predicted more prolonged accumulating survival in sepsis patients.

CONCLUSION

JNK pathway-associated phosphatase is of good value in predicting lower sepsis risk, and its downregulation correlates with advanced disease severity, higher level of systemic inflammation, and poor survival in sepsis patients.

Genome-wide analysis identifies rare copy number variations associated with inflammatory bowel disease

Background

Inflammatory bowel disease (IBD) is an idiopathic, chronic disorder of unclear etiology with an underlying genetic predisposition. Recent genome-wide association studies have identified more than 200 IBD susceptibility loci, but the causes of IBD remain poorly defined. We hypothesized that rare (<0.1% population frequency) gene copy number variations (CNVs) could play an important mechanism for risk of IBD. We aimed to examine changes in DNA copy number in a population-based cohort of patients with IBD and search for novel genetic risk factors for IBD.

Methods

DNA samples from 243 individuals with IBD from the Manitoba IBD Cohort Study and 2988 healthy controls were analyzed using genome-wide SNP microarray technology. Three CNV calling algorithms were applied to maximize sensitivity and specificity of CNV detection. We identified IBD-associated genes affected by rare CNV from comparing the number of overlapping CNVs in IBD samples with the number of overlapping CNVs in controls for each gene.

Results

4,402 CNVs detected by two or three algorithms intersected 7,061 genes, in at least one analyzed sample. Four genes (e.g. DUSP22 and IP6K3) intersected by rare deletions and fourteen genes (e.g. SLC25A10, PSPN, GTF2F1) intersected by rare duplications demonstrated significant association with IBD (FDR-adjusted p-value < 0.01). Of these, ten genes were functionally related to immune response and intracellular signalling pathways. Some of these genes were also identified in other IBD related genome-wide association studies. These suggested that the identified genes may play a role in the risk of IBD.

Conclusion

Our results revealed new genomic loci associated with IBD, which suggested the role of rare CNVs in IBD risk.

Dual-Specificity Phosphatases in Immunity and Infection: An Update

Kinase activation and phosphorylation cascades are key to initiate immune cell activation in response to recognition of antigen and sensing of microbial danger. However, for balanced and controlled immune responses, the intensity and duration of phospho-signaling has to be regulated. The dual-specificity phosphatase (DUSP) gene family has many members that are differentially expressed in resting and activated immune cells. Here, we review the progress made in the field of DUSP gene function in regulation of the immune system during the last decade. Studies in knockout mice have confirmed the essential functions of several DUSP-MAPK phosphatases (DUSP-MKP) in controlling inflammatory and anti-microbial immune responses and support the concept that individual DUSP-MKP shape and determine the outcome of innate immune responses due to context-dependent expression and selective inhibition of different mitogen-activated protein kinases (MAPK). In addition to the canonical DUSP-MKP, several small-size atypical DUSP proteins regulate immune cells and are therefore also reviewed here. Unexpected and complex findings in DUSP knockout mice pose new questions regarding cell type-specific and redundant functions. Another emerging question concerns the interaction of DUSP-MKP with non-MAPK binding partners and substrate proteins. Finally, the pharmacological targeting of DUSPs is desirable to modulate immune and inflammatory responses.

Regulation of Dual-Specificity Phosphatase (DUSP) Ubiquitination and Protein Stability

Mitogen-activated protein kinases (MAPKs) are key regulators of signal transduction and cell responses. Abnormalities in MAPKs are associated with multiple diseases. Dual-specificity phosphatases (DUSPs) dephosphorylate many key signaling molecules, including MAPKs, leading to the regulation of duration, magnitude, or spatiotemporal profiles of MAPK activities. Hence, DUSPs need to be properly controlled. Protein post-translational modifications, such as ubiquitination, phosphorylation, methylation, and acetylation, play important roles in the regulation of protein stability and activity. Ubiquitination is critical for controlling protein degradation, activation, and interaction. For DUSPs, ubiquitination induces degradation of eight DUSPs, namely, DUSP1, DUSP4, DUSP5, DUSP6, DUSP7, DUSP8, DUSP9, and DUSP16. In addition, protein stability of DUSP2 and DUSP10 is enhanced by phosphorylation. Methylation-induced ubiquitination of DUSP14 stimulates its phosphatase activity. In this review, we summarize the knowledge of the regulation of DUSP stability and ubiquitination through post-translational modifications.

Induction of DUSP14 ubiquitination by PRMT5-mediated arginine methylation

Dual-specificity phosphatase (DUSP)14 (also known as MAP-kinase phosphatase 6) inhibits T-cell receptor (TCR) signaling and T-cell-mediated immune responses by inactivation of the TGF-β activated kinase 1 binding protein (TAB1)-TGF-β activated kinase 1 (TAK1) complex and ERK. DUSP14 phosphatase activity is induced by the E3 ligase TNF receptor associated factor (TRAF)2-mediated Lys63-linked ubiquitination. Here we report an interaction between DUSP14 and protein arginine methyltransferase (PRMT)5 by proximity ligation assay; similarly, DUSP14 directly interacted with TAB1 but not TAK1. DUSP14 is methylated by PRMT5 at arginine 17, 38, and 45 residues. The DUSP14 triple-methylation mutant was impaired in PRMT5-mediated arginine methylation, TRAF2-mediated lysine ubiquitination, and DUSP14 phosphatase activity. Consistently, DUSP14 methylation, TRAF2 binding, and DUSP14 ubiquitination were attenuated by PRMT5 short hairpin RNA knockdown. Furthermore, DUSP14 was inducibly interacted with PRMT5 and was methylated during TCR signaling in T cells. Together, these findings reveal a novel regulatory mechanism of DUSP14 by which PRMT5-mediated arginine methylation may sequentially stimulate TRAF2-mediated DUSP14 ubiquitination and phosphatase activity, leading to inhibition of TCR signaling.-Yang, C.-Y., Chiu, L.-L., Chang, C.-C., Chuang, H.-C., Tan, T.-H. Induction of DUSP14 ubiquitination by PRMT5-mediated arginine methylation.

Elevated plasma midkine and pleiotrophin levels in patients with systemic lupus erythematosus

Emerging evidence suggests that two heparin-binding growth factor, midkine and pleiotrophin are implicated in the pathogenesis of autoimmune diseases including SLE. To investigate the plasma midkine and pleiotrophin levels in SLE patients, as well as their correlation with major clinical parameters and interleukin-17 (IL-17) level in SLE, 83 SLE patients and 123 controls including 20 rheumatoid arthritis (RA) patients, 21 Sjögren's syndrome (SS) patients and 82 healthy controls (HCs) were recruited. Plasma midkine, pleiotrophin and IL-17 levels were detected by ELISA. Midkine and pleiotrophin levels were significantly higher in SLE, RA and SS patients compared with HCs (all P < 0.05). There were significantly lower midkine and pleiotrophin levels in SLE compared to SS (P < 0.05 and P < 0.01, respectively). No significant differences in midkine and pleiotrophin levels were found between SLE and RA (P = 0.240 and P = 0.074, respectively). Both plasma midkine and pleiotrophin levels were associated with rash and anti-SSA in SLE. In addition, both midkine and pleiotrophin levels were positively associated with IL-17 level in SLE (both P < 0.001). Area under curve (AUC) of the receiver operating characteristic (ROC) curve for midkine and pleiotrophin were 0.606 (0.527–0.681) and 0.605 (0.526–0.680) respectively. In conclusion, elevated plasma midkine and pleiotrophin levels and their associations with rash, anti-SSA and IL-17 in SLE patients suggest their involvement in this disease.

Association of long noncoding RNAs expression levels and their gene polymorphisms with systemic lupus erythematosus

Increasing evidence has demonstrated the association between long noncoding RNAs (lncRNAs) and multiple autoimmune diseases. To explore four lncRNAs (GAS5, lnc-DC, linc0597 and linc0949) expression levels and gene polymorphisms in systemic lupus erythematosus (SLE), a two stage design was applied. In the first stage, 85 SLE patients and 71 healthy controls were enrolled to investigate the lncRNAs expression levels. Then, 1260 SLE patients and 1231 healthy controls were included to detect the single nucleotide polymorphisms (SNPs) in the differentially expressed lncRNAs identified in the first stage. Linc0597, lnc-DC and GAS5 expression levels were significantly lower in SLE patients than healthy controls (P < 0.001, P < 0.001, P = 0.003 respectively). Association of five SNPs (rs10515177, rs2070107, rs2632516, rs2877877, rs2067079) with SLE risk were analyzed. No significant association was observed between these gene polymorphisms and susceptibility to SLE (all P > 0.010), and we did not find significant association between any genotypes at five SNPs and their respective lncRNAs expression in SLE (all P > 0.010). In summary, the expression levels of linc0597, lnc-DC and GAS5 are decreased in SLE patients, but their gene polymorphisms are not associated with SLE risk, and do not influence their expression levels.

JNK Pathway-Associated Phosphatase/DUSP22 Suppresses CD4+ T-Cell Activation and Th1/Th17-Cell Differentiation and Negatively Correlates with Clinical Activity in Inflammatory Bowel Disease

This study aimed to investigate the role of JNK pathway-associated phosphatase (JKAP) in inflammatory bowel disease (IBD). JKAP expression was analyzed in the intestinal mucosa of 81 IBD patients and 25 healthy controls (HCs) by qPCR and immunoblotting. The correlations of JKAP with clinical activity and inflammatory cytokines were performed. JKAP expression before and after infliximab treatment was also measured. CD4⁺ T cells were isolated from peripheral blood in active IBD patient and HCs and transduced with lentivirus-encoding JKAP (LV-JKAP), anti-JKAP (LV-anti-JKAP), or empty vector (LV-scramble), and JKAP functions on IBD CD4⁺ T cells were subsequently investigated. JKAP expression was decreased in inflamed mucosa of active IBD patients and was negatively correlated with disease activity [Crohn’s disease activity index (CDAI), Mayo index, C-reactive protein, and erythrocyte sedimentation rate], interleukin-17, and tumor necrosis factor (TNF)-α levels. Anti-TNF-α treatment up-regulated JKAP expression in CD patients, and baseline JKAP expression was elevated in response patients than in failure patients. Transduction of LV-JKAP into CD4⁺ T cells inhibited the percentages of CD25⁺ and CD69⁺ cells and proliferation. Moreover, inhibition of JKAP promotes Th1/Th17 cell differentiation. Our data indicated that the decreased expression of JKAP in intestinal mucosa contributed to the pathogenesis of IBD, through facilitating CD4⁺ T-cell activation, proliferation, and Th1/Th17-cell differentiation.

Gene Expression Profiles of Human Phosphotyrosine Phosphatases Consequent to Th1 Polarisation and Effector Function

Phosphotyrosine phosphatases (PTPs) constitute a complex family of enzymes that control the balance of intracellular phosphorylation levels to allow cell responses while avoiding the development of diseases. Despite the relevance of CD4 T cell polarisation and effector function in human autoimmune diseases, the expression profile of PTPs during T helper polarisation and restimulation at inflammatory sites has not been assessed. Here, a systematic analysis of the expression profile of PTPs has been carried out during Th1-polarising conditions and upon PKC activation and intracellular raise of Ca²⁺ in effector cells. Changes in gene expression levels suggest a previously nonnoted regulatory role of several PTPs in Th1 polarisation and effector function. A substantial change in the spatial compartmentalisation of ERK during T cell responses is proposed based on changes in the dose of cytoplasmic and nuclear MAPK phosphatases. Our study also suggests a regulatory role of autoimmune-related PTPs in controlling T helper polarisation in humans. We expect that those PTPs that regulate T helper polarisation will constitute potential targets for intervening CD4 T cell immune responses in order to generate new therapies for the treatment of autoimmune diseases.