Tamm-Horsfall protein (THP), or uromodulin (UMOD), is an 80-90-kDa phosphatidylinositol-anchored glycoprotein produced exclusively by the renal tubular cells in the thick ascending limb of the loop ...of Henle. Physiologically, THP is implicated in renal countercurrent gradient formation, sodium homeostasis, blood pressure regulation, and a defense molecule against infections in the urinary system. Investigations have also revealed that THP is an effective binding ligand for serum albumin, immunoglobulin G light chains, complement components C1 and C1q, interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, and interferon-γ through its carbohydrate side chains for maintaining circulatory and renal immune homeostasis. Thus, THP can be regarded as part of the innate immune system.
mutations play crucial roles in congenital urolithiasis, hereditary hyperuricemia/gout, and medullary cystic kidney diseases. Recent investigations have focused on the immunomodulatory effects of THP on immune cells and on THP as a disease biomarker of acute and chronic kidney diseases. Our studies have suggested that normal urinary THP, through its epidermal growth factor (EGF)-like domains, binds to the surface-expressed EGF-like receptors, cathepsin G, or lactoferrin to enhance polymorphonuclear leukocyte phagocytosis, proinflammatory cytokine production by monocytes/macrophages, and lymphocyte proliferation by activating the
family and mitogen-activated protein kinase signaling pathways. Furthermore, our data support both an intact protein core structure and carbohydrate side chains are important for the different protein-binding capacities of THP. Prospectively, parts of the whole THP molecule may be used for anti-TNF-α therapy in inflammatory diseases, autoantibody-depleting therapy in autoimmune disorders, and immune intensification in immunocompromised hosts.
•The estimated prevalence of sarcopenia in RA was 31%, without significant differences between various living area and diagnostic modalities.•Disease duration, DAS28 and HAQ were predictors of ...sarcopenia development in patients with RA.•Functional limitation, CRP and RF seropositivity were identified as additional risk factors.
Sarcopenia is an ever-increasingly recognized entity in aging or chronically-ill individuals. A recent surge of researches came out on sarcopenia in rheumatoid arthritis (RA). However, the results varied widely. We tried to assess the prevalence of and associated factors with sarcopenia in patients with RA.
We searched the investigations dealing with the prevalence of and associated factors with sarcopenia in RA from PubMed, EMBASE, CENTRAL, EBSCOhost, Airiti Library, CEPS, CNKI and J-STAGE from the inception to January 11, 2020. Effects regarding prevalence and associated factors were extracted and evaluated by random-effects model. Sensitivity analysis was also performed.
Seventeen studies containing 3,140 RA subjects were identified. After exclusion of outliers, the pooled prevalence of sarcopenia was 31%. Neither ongoing-study districts nor diagnostic modalities affected prevalence significantly. Any associated factors being mentioned in at least two publications were analyzed, yielding functional limitation (Steinbrocker stage III/IV), high CRP and RF seropositivity as the significant risk factors. Based on disease durations, we carried out meta-regression and found DAS28 and HAQ are predictive models. There was no alteration in the interpretation of results from sensitivity analysis after removal of any studies skewed in sampling distribution.
The prevalence of sarcopenia in patients with RA is high, compared to that in general counterparts. Disease duration rather than age, residing area or diagnostic modalities influences sarcopenia development; DAS28 and HAQ predict occurrence. High index of suspicion to facilitate early detection of sarcopenia in RA patients is important.
Polymorphonuclear neutrophils (PMNs) are traditionally regarded as professional phagocytic and acute inflammatory cells that engulf the microbial pathogens. However, accumulating data have suggested ...that PMNs are multi-potential cells exhibiting many important biological functions in addition to phagocytosis. These newly found novel activities of PMN include production of different kinds of cytokines/chemokines/growth factors, release of neutrophil extracellular traps (NET)/ectosomes/exosomes and trogocytosis (membrane exchange) with neighboring cells for modulating innate, and adaptive immune responses. Besides, PMNs exhibit potential heterogeneity and plasticity in involving antibody-dependent cellular cytotoxicity (ADCC), cancer immunity, autoimmunity, inflammatory rheumatic diseases, and cardiovascular diseases. Interestingly, PMNs may also play a role in ameliorating inflammatory reaction and wound healing by a subset of PMN myeloid-derived suppressor cells (PMN-MDSC). Furthermore, PMNs can interact with other non-immune cells including platelets, epithelial and endothelial cells to link hemostasis, mucosal inflammation, and atherogenesis. The release of low-density granulocytes (LDG) from bone marrow initiates systemic autoimmune reaction in systemic lupus erythematosus (SLE). In clinical application, identification of certain PMN phenotypes may become prognostic factors for severe traumatic patients. In the present review, we will discuss these newly discovered biological and pathobiological functions of the PMNs.
Objective
Phthalates induce inflammation and are ubiquitously used in daily life. We aim to study the impact of di‐(2‐ethylhexyl) phthalate (DEHP) exposure on inflammation and osteoporosis in ...premenopausal and postmenopausal females.
Methods
Female 8‐week‐old C57BL/6JNarl mice received an ovariectomy (OVX) or a sham operation and were fed with DEHP or vehicle by oral gavage for 4 or 8 weeks. Their femurs were isolated for micro‐computed tomography, and their serum was collected for inflammatory cytokine assays. Correlations between urinary phthalate metabolites and the lumbar spine bone mineral density (BMD) in premenopausal and postmenopausal volunteers were performed.
Results
Among the OVX mice treated for 4 weeks, significant lower bone volume, bone volume/tissue volume, and trabecular number but significant higher trabecular bone pattern factor and structure model index were identified in the mice treated with DEHP than with vehicle. The OVX mice treated with DEHP for 4 weeks had significantly higher serum interleukin (IL)‐1β, IL‐10, IL‐17A, interferon (IFN)‐γ, tumor necrosis factor (TNF)‐α, and Dickkopf‐1 levels than those treated with vehicle. The sham mice treated with DEHP for 8 weeks showed an impaired femur trabecular microstructure and had significantly higher serum IL‐1β, IL‐6, IL‐10, IL‐17A, IFN‐γ, and TNF‐α than those treated with vehicle. DEHP metabolites were inversely correlated with the BMD of premenopausal women and the T‐score of postmenopausal women.
Conclusion
DEHP treatment in OVX and sham mice results in osteoporosis and impairs the microstructure of the femur trabecula through inflammation. Phthalate exposure negatively affects the bone mass in both premenopausal and postmenopausal women. Thus, long‐term avoidance is suggested.
Signaling driven by nucleic acid sensors participates in interferonopathy-mediated autoimmune diseases. NLRP12, a pyrin-containing NLR protein, is a negative regulator of innate immune activation and ...type I interferon (IFN-I) production. Peripheral blood mononuclear cells (PBMCs) derived from systemic lupus erythematosus (SLE) patients expressed lower levels of NLRP12, with an inverse correlation with IFNA expression and high disease activity. NLRP12 expression was transcriptionally suppressed by runt-related transcription factor 1-dependent (RUNX1-dependent) epigenetic regulation under IFN-I treatment, which enhanced a negative feedback loop between low NLRP12 expression and IFN-I production. Reduced NLRP12 protein levels in SLE monocytes was linked to spontaneous activation of innate immune signaling and hyperresponsiveness to nucleic acid stimulations. Pristane-treated Nlrp12-/- mice exhibited augmented inflammation and immune responses; and substantial lymphoid hypertrophy was characterized in NLRP12-deficient lupus-prone mice. NLRP12 deficiency mediated the increase of autoantibody production, intensive glomerular IgG deposition, monocyte recruitment, and the deterioration of kidney function. These were bound in an IFN-I signature-dependent manner in the mouse models. Collectively, we reveal a remarkable link between low NLRP12 expression and lupus progression, which suggests the impact of NLRP12 on homeostasis and immune resilience.
Patients with systemic lupus erythematosus (SLE) are susceptible to herpes simplex virus (HSV) infection, which occasionally leads to severe complications including meningoencephalitis and keratitis. ...However, few attempts to analyse the associated incidence and risk factors have been made.
We enrolled patients with SLE recorded between 1997 and 2012 and compared the incidence rate (IR) of severe HSV infection, including meningoencephalitis, septicaemia, ocular and visceral involvement, and other specific complications demanding hospitalisation, with that of a non-SLE cohort. A Cox multivariate proportional hazards model was applied to analyse the risk factors of severe HSV infection in patients with SLE.
A total of 122 520 subjects (24 504 patients with SLE and 98 016 age-matched and sex-matched non-SLE controls) were included, and a higher IR of severe HSV infection was revealed in the SLE group (IR ratio=3.93, p<0.001). In patients with SLE, previous oral and genital infection (HR=2.29, p=0.049), intravenous steroid pulse therapy (HR=5.32, p<0.001) and daily oral dose of over 7.5 mg of prednisolone (HR=1.59, p=0.024) were independent risk factors for severe HSV infection, whereas age of ≤18 (HR=0.45, p=0.029) was a protective factor.
Patients with SLE are at higher risk of severe HSV infection, and related risk factors include being older than 18 years, having a history of HSV mucocutaneous infection, recent receipt of steroid pulse therapy and a daily oral dose of steroid over 7.5 mg prednisolone.
Lupus nephritis (LN) is one of the most severe complications in patients with systemic lupus erythematosus (SLE). Traditionally, LN is regarded as an immune complex (IC) deposition disease led by ...dsDNA-anti-dsDNA-complement interactions in the subendothelial and/or subepithelial basement membrane of glomeruli to cause inflammation. The activated complements in the IC act as chemoattractants to chemically attract both innate and adaptive immune cells to the kidney tissues, causing inflammatory reactions. However, recent investigations have unveiled that not only the infiltrating immune-related cells, but resident kidney cells, including glomerular mesangial cells, podocytes, macrophage-like cells, tubular epithelial cells and endothelial cells, may also actively participate in the inflammatory and immunological reactions in the kidney. Furthermore, the adaptive immune cells that are infiltrated are genetically restricted to autoimmune predilection. The autoantibodies commonly found in SLE, including anti-dsDNA, are cross-reacting with not only a broad spectrum of chromatin substances, but also extracellular matrix components, including α-actinin, annexin II, laminin, collagen III and IV, and heparan sulfate proteoglycan. Besides, the glycosylation on the Fab portion of IgG anti-dsDNA antibodies can also affect the pathogenic properties of the autoantibodies in that α-2,6-sialylation alleviates, whereas fucosylation aggravates their nephritogenic activity. Some of the coexisting autoantibodies, including anti-cardiolipin, anti-C1q, anti-ribosomal P autoantibodies, may also enhance the pathogenic role of anti-dsDNA antibodies. In clinical practice, the identification of useful biomarkers for diagnosing, monitoring, and following up on LN is quite important for its treatments. The development of a more specific therapeutic strategy to target the pathogenic factors of LN is also critical. We will discuss these issues in detail in the present article.
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