Sex Differences in monocytes and TLR4 associated immune responses; implications for systemic lupus erythematosus (SLE)

Sex-specific association between monocyte to high-density lipoprotein cholesterol and extensive abdominal aortic calcification in humans

Recent studies have identified monocyte-to-high-density lipoprotein cholesterol ratio (MHR) as a simple marker of atherosclerosis. Abdominal aortic calcification (AAC) is a direct result of vascular atherosclerosis. Our study aims to investigate the association between MHR and the prevalent extensive AAC and assess the value of MHR for identifying prevalent extensive AAC. 2857 subjects (28.07%) from the cross-sectional National Health and Nutrition Examination Survey 2013-2014 were included in our study. AAC was detected through dual-energy x-ray absorptiometry and quantified by Kauppila score. Extensive AAC was identified in 153 (10.44% of 1465) females and 146 (10.49% of 1392) males. With the full adjustment, each SD increase of MHR resulted in an 87.3% additional risk for extensive AAC in females. When dividing into quartiles, the top quartile had a 3.472 times risk of prevalent extensive AAC than the bottom quartile. However, no significant association was observed in males. Furthermore, smooth curve fitting implicated that the significant association was linear in the whole range of MHR among females. Additionally, ROC demonstrated an improvement in the identification of extensive AAC only among females when introducing MHR into established risk factors of atherosclerosis (0.808 vs. 0.864, p < 0.001). Finally, category-free net reclassification index and integrated discrimination index also supported the improvement by MHR in females. Our study revealed a linear association between MHR and prevalent extensive AAC in females. Moreover, our results implicated the potential value of MHR to refine the identification of prevalent extensive AAC in females.

Neurosteroid [3α,5α]-3-hydroxy-pregnan-20-one enhances IL-10 production via endosomal TRIF-dependent TLR4 signaling pathway

Background

Previous studies demonstrated the inhibitory effect of allopregnanolone (3α,5α-THP) on the activation of inflammatory toll-like receptor 4 (TLR4) signals in RAW264.7 macrophages and the brains of selectively bred alcohol-preferring (P) rats. In the current study, we investigated the impact of 3α,5α-THP on the levels of IL-10 and activation of the TRIF-dependent endosomal TLR4 pathway.

Methods

The amygdala and nucleus accumbens (NAc) of P rats, which exhibit innately activated TLR4 pathways as well as RAW264.7 cells, were used. Enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays were used to ascertain the effects of 3α,5α-THP on the TRIF-dependent endosomal TLR4 pathway and endosomes were isolated to examine translocation of TLR4 and TRIF. Additionally, we investigated the effects of 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) on the levels of IL-10 in RAW264.7 macrophages. Finally, we examined whether inhibiting TRIF (using TRIF siRNA) in RAW264.7 cells altered the levels of IL-10.

Results

3α,5α-THP administration facilitated activation of the endosomal TRIF-dependent TLR4 pathway in males, but not female P rats. 3α,5α-THP increased IL-10 levels (+13.2 ± 6.5%) and BDNF levels (+21.1 ± 11.5%) in the male amygdala. These effects were associated with increases in pTRAM (+86.4 ± 28.4%), SP1 (+122.2 ± 74.9%), and PI(3)K-p110δ (+61.6 ± 21.6%), and a reduction of TIRAP (-13.7 ± 6.0%), indicating the activation of the endosomal TRIF-dependent TLR4 signaling pathway. Comparable effects were observed in NAc of these animals. Furthermore, 3α,5α-THP enhanced the accumulation of TLR4 (+43.9 ± 11.3%) and TRIF (+64.8 ± 32.8%) in endosomes, with no significant effect on TLR3 accumulation. Additionally, 3α,5α-THP facilitated the transition from early endosomes to late endosomes (increasing Rab7 levels: +35.8 ± 18.4%). In RAW264.7 cells, imiquimod (30 µg/mL) reduced IL-10 while 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) restored IL-10 levels. To determine the role of the TRIF-dependent TLR4 signaling pathway in IL-10 production, the downregulation of TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%). TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%) and 3α,5α-THP (1.0 µM) no longer restored the reduced IL-10 levels.

Conclusion

The results demonstrate 3α,5α-THP enhancement of the endosomal TLR4-TRIF anti-inflammatory signals and elevations of IL-10 in male P rat brain that were not detected in female P rat brain. These effects hold significant implications for controlling inflammatory responses in both the brain and peripheral immune cells.

TAK-242, a toll-like receptor 4 antagonist, against brain injury by alleviates autophagy and inflammation in rats

Inhibition of Toll-like receptor 4 (TLR4)-mediated inflammatory pathways exerts a critical effect on neuronal death; therefore, it is a possible new therapeutic approach for traumatic brain injury (TBI). Resatorvid (TAK-242) is a novel small-molecule compound widely used to inhibit TLR4-mediated pathways, but the protective mechanism of TAK-242 in TBI remains unclear. Herein, we analyzed the neuroprotective effects of TAK-242 in rats after TBI. The rat model of brain injury was established using a modified Free-fall device, and the rats were injected with TAK-242 (0.5 mg/kg) through the caudal vein before TBI. The rats were allocated into four groups: a sham group, a TBI group, a TBI + vehicle group, and a TBI + TAK-242 group. The brain tissue was extracted for histology and determination of the expression of autophagy-related proteins and inflammatory mediators. TAK-242 pretreatment significantly reduced the damage to hippocampal neurons. Neuronal autophagy increased after brain injury, whereas TAK-242 significantly reduced autophagy marker protein LC3-II in the hippocampus. In addition, TAK-242 pretreatment significantly downregulated NF-κB p65, TNF-α, and IL-1β in the hippocampus. In conclusion, TAK-242 significantly reduced hippocampal neuronal damage by inhibiting autophagy and neuroinflammatory activity, possibly via the NF-κB signaling pathway.

Lipidome modulation by dietary omega-3 polyunsaturated fatty acid supplementation or selective soluble epoxide hydrolase inhibition suppresses rough LPS-accelerated glomerulonephritis in lupus-prone mice

Introduction

Lipopolysaccharide (LPS)-accelerated autoimmune glomerulonephritis (GN) in NZBWF1 mice is a preclinical model potentially applicable for investigating lipidome-modulating interventions against lupus. LPS can be expressed as one of two chemotypes: smooth LPS (S-LPS) or rough LPS (R-LPS) which is devoid of O-antigen polysaccharide sidechain. Since these chemotypes differentially affect toll-like receptor 4 (TLR4)-mediated immune cell responses, these differences may influence GN induction.

Methods

We initially compared the effects of subchronic intraperitoneal (i.p.) injection for 5 wk with 1) Salmonella S-LPS, 2) Salmonella R-LPS, or 3) saline vehicle (VEH) (Study 1) in female NZBWF1 mice. Based on the efficacy of R-LPS in inducing GN, we next used it to compare the impact of two lipidome-modulating interventions, ω-3 polyunsaturated fatty acid (PUFA) supplementation and soluble epoxide hydrolase (sEH) inhibition, on GN (Study 2). Specifically, effects of consuming ω-3 docosahexaenoic acid (DHA) (10 g/kg diet) and/or the sEH inhibitor 1-(4-trifluoro-methoxy-phenyl)-3-(1-propionylpiperidin-4-yl) urea (TPPU) (22.5 mg/kg diet ≈ 3 mg/kg/day) on R-LPS triggering were compared.

Results

In Study 1, R-LPS induced robust elevations in blood urea nitrogen, proteinuria, and hematuria that were not evident in VEH- or S-LPS-treated mice. R-LPS-treated mice further exhibited kidney histopathology including robust hypertrophy, hyperplasia, thickened membranes, lymphocytic accumulation containing B and T cells, and glomerular IgG deposition consistent with GN that was not evident in VEH- or SLPS-treated groups. R-LPS but not S-LPS induced spleen enlargement with lymphoid hyperplasia and inflammatory cell recruitment in the liver. In Study 2, resultant blood fatty acid profiles and epoxy fatty acid concentrations reflected the anticipated DHA- and TPPU-mediated lipidome changes, respectively. The relative rank order of R-LPS-induced GN severity among groups fed experimental diets based on proteinuria, hematuria, histopathologic scoring, and glomerular IgG deposition was: VEH/CON< R-LPS/DHA ≈ R-LPS/TPPU<<< R-LPS/TPPU+DHA ≈ R-LPS/CON. In contrast, these interventions had modest-to- negligible effects on R-LPS-induced splenomegaly, plasma antibody responses, liver inflammation, and inflammation-associated kidney gene expression.

Discussion

We show for the first time that absence of O-antigenic polysaccharide in R-LPS is critical to accelerated GN in lupus-prone mice. Furthermore, intervention by lipidome modulation through DHA feeding or sEH inhibition suppressed R-LPS-induced GN; however, these ameliorative effects were greatly diminished upon combining the treatments.

eNAMPT/TLR4 inflammatory cascade activation is a key contributor to SLE Lung vasculitis and alveolar hemorrhage

Rationale

Effective therapies to reduce the severity and high mortality of pulmonary vasculitis and diffuse alveolar hemorrhage (DAH) in patients with systemic lupus erythematosus (SLE) is a serious unmet need. We explored whether biologic neutralization of eNAMPT (extracellular nicotinamide phosphoribosyl-transferase), a novel DAMP and Toll-like receptor 4 ligand, represents a viable therapeutic strategy in lupus vasculitis.

Methods

Serum was collected from SLE subjects (n = 37) for eNAMPT protein measurements. In the preclinical pristane-induced murine model of lung vasculitis/hemorrhage, C57BL/6 J mice (n = 5-10/group) were treated with PBS, IgG (1 mg/kg), or the eNAMPT-neutralizing ALT-100 mAb (1 mg/kg, IP or subcutaneously (SQ). Lung injury evaluation (Day 10) included histology/immuno-histochemistry, BAL protein/cellularity, tissue biochemistry, RNA sequencing, and plasma biomarker assessment.

Results

SLE subjects showed highly significant increases in blood NAMPT mRNA expression and eNAMPT protein levels compared to healthy controls. Preclinical pristane-exposed mice studies showed significantly increased NAMPT lung tissue expression and increased plasma eNAMPT levels accompanied by marked increases in alveolar hemorrhage and lung inflammation (BAL protein, PMNs, activated monocytes). In contrast, ALT-100 mAb-treated mice showed significant attenuation of inflammatory lung injury, alveolar hemorrhage, BAL protein, tissue leukocytes, and plasma inflammatory cytokines (eNAMPT, IL-6, IL-8). Lung RNA sequencing showed pristane-induced activation of inflammatory genes/pathways including NFkB, cytokine/chemokine, IL-1β, and MMP signaling pathways, each rectified in ALT-100 mAb-treated mice.

Conclusions

These findings highlight the role of eNAMPT/TLR4-mediated inflammatory signaling in the pathobiology of SLE pulmonary vasculitis and alveolar hemorrhage. Biologic neutralization of this novel DAMP appears to serve as a viable strategy to reduce the severity of SLE lung vasculitis.

Stress, mindfulness, and systemic lupus erythematosus: An overview and directions for future research

Although the pathogenesis of autoimmunity is not fully understood, it is thought to involve genetic, hormonal, immunologic, and environmental factors. Stress has been evaluated as a potential trigger for autoimmunity and disease flares in patients with systemic lupus erythematosus (SLE). The physiologic changes that occur with stress involve numerous catecholamines, hormones, and cytokines that communicate intricately with the immune system. There is some evidence that these systems may be dysregulated in patients with autoimmune disease. Mindfulness-based techniques are practices aimed at mitigating stress response and have been shown to improve quality of life in general population. This review will discuss pathophysiology of chronic stress as it relates to SLE, evidence behind mindfulness-based practices in these patients, and directions for future research.

The effect of sex, menstrual cycle phase and oral contraceptive use on intestinal permeability and ex-vivo monocyte TNFα release following treatment with lipopolysaccharide and hyperthermia

PURPOSE

Investigate the impact of sex, menstrual cycle phase and oral contraceptive use on intestinal permeability and ex-vivo tumour necrosis factor alpha (TNFα) release following treatment with lipopolysaccharide (LPS) and hyperthermia.

METHODS

Twenty-seven participants (9 men, 9 eumenorrheic women (MC) and 9 women taking an oral contraceptive pill (OC)) completed three trials. Men were tested on 3 occasions over 6 weeks; MC during early-follicular, ovulation, and mid-luteal phases; OC during the pill and pill-free phase. Intestinal permeability was assessed following a 4-hour dual sugar absorption test (lactulose: rhamnose). Venous blood was collected each trial and stimulated with 100 μg·mL^-1 LPS before incubation at 37 °C and 40 °C and analysed for TNFα via ELISA.

RESULTS

L:R ratio was higher in OC than MC (+0.003, p = 0.061) and men (+0.005, p = 0.007). Men had higher TNFα responses than both MC (+53 %, p = 0.004) and OC (+61 %, p = 0.003). TNFα release was greater at 40 °C than 37 °C (+23 %, p < 0.001).

CONCLUSIONS

Men present with lower resting intestinal barrier permeability relative to women regardless of OC use and displayed greater monocyte TNFα release following whole blood treatment with LPS and hyperthermia. Oral contraceptive users had highest intestinal permeability however, neither permeability or TNFα release were impacted by the pill cycle. Although no statistical effect was seen in the menstrual cycle, intestinal permeability and TNFα release were more variable across the phases.

Monocytes in central nervous system remyelination

Remyelination failure with aging and progression of neurodegenerative disorders contributes to axonal dysfunction, highlighting the importance of understanding the mechanisms underpinning this process to develop regenerative therapies. Central nervous system (CNS) macrophages, encompassing both resident microglia and blood monocyte-derived cells, play a crucial role in driving successful remyelination. Although there has been a focus on the critical roles of microglia in remyelination, the specific contribution of monocyte-derived macrophages is still not fully understood. Until recently, the lack of tools enabling distinction between CNS macrophage populations has hindered our understanding of monocyte influence on remyelination. Recent advances have allowed for identification and characterization of monocyte populations in health, aging and in neurodegenerative conditions like multiple sclerosis, indicating heterogeneity of monocyte subsets impacted by both intrinsic and extrinsic factors. Here, we discuss the new tools enabling distinction between macrophage populations and advancements in understanding the importance of monocytes in remyelination, and reflect on the potential for therapeutic targeting of monocytes to promote remyelination.

Revealing the Influences of Sex Hormones and Sex Differences in Atrial Fibrillation and Vascular Cognitive Impairment

The impacts of sex differences on the biology of various organ systems and the influences of sex hormones on modulating health and disease have become increasingly relevant in clinical and biomedical research. A growing body of evidence has recently suggested fundamental sex differences in cardiovascular and cognitive function, including anatomy, pathophysiology, incidence and age of disease onset, symptoms affecting disease diagnosis, disease severity, progression, and treatment responses and outcomes. Atrial fibrillation (AF) is currently recognized as the most prevalent sustained arrhythmia and might contribute to the pathogenesis and progression of vascular cognitive impairment (VCI), including a range of cognitive deficits, from mild cognitive impairment to dementia. In this review, we describe sex-based differences and sex hormone functions in the physiology of the brain and vasculature and the pathophysiology of disorders therein, with special emphasis on AF and VCI. Deciphering how sex hormones and their receptor signaling (estrogen and androgen receptors) potentially impact on sex differences could help to reveal disease links between AF and VCI and identify therapeutic targets that may lead to potentially novel therapeutic interventions early in the disease course of AF and VCI.

Immune receptor toll-like receptor 4 contributes to stress-induced affective responses in a sex-specific manner

Stress activates innate immune Toll-like receptors (TLRs) and enhances susceptibility to depression, a condition that is more prevalent in females. The TLR4 receptor type is involved in inflammatory responses and its expression levels associate with depressive symptoms and their successful treatment. Yet, little preclinical research has examined the role of TLR4 in stress-induced affective responses to determine if these are sex-specific. One group per genotype of male and female Tlr4 knockout (KO) and wild type (WT) rats were exposed to predator odor in a place conditioning apparatus with others exposed to saline. Affective behaviors evaluated included distance traveled and center time in an open-field apparatus, sucrose preference and fluid intake in a two-bottle test, and conditioned place aversion to the odor-paired compartment. Predator odor exposed rats showed conditioned place aversion to the odor-paired compartment, demonstrating predator odor was aversive. Such exposure led to anhedonia (decreased sucrose preference) across genotypes and sex. Predator odor exposure decreased distance traveled, an effect that was greater in KO rats, especially in females. Tlr4 deletion also resulted in sex-specific effects on anxiety-like behavior. Compared to WTs, female KO rats showed lower center time after predator odor exposure whereas genotype did not affect this response in male rats. Across litters, fewer male KO and heterozygous rats and more WT rats were born whereas female rats showed the typical genotype distribution. Results suggest predator odor alters affective behaviors, consistent with the preclinical literature, and deletion of Tlr4 enhances some stress-induced affective responses, often in a sex-specific manner.

Toll-Like Receptors Contribute to Sex Differences in Blood Pressure Regulation

Toll-like receptors (TLRs) play an important role in the innate immune system, and recently, they have been shown to be involved in the regulation of blood pressure. The incidence of hypertension is higher in men, and it increases in postmenopausal women. In fact, premenopausal women are protected from cardiovascular disease compared with age-matched men, and it is well established that this protective effect is lost with menopause. However, the molecular mechanisms underlying this protection in women are unknown. Whether or not it could be related to differential activation of the innate immune system remains to be elucidated. This review focuses on (1) the differences between men and women in TLR activation and (2) whether TLR activation may influence the regulation of blood pressure in a sex-dependent manner.

Synergistic Activation of Toll-Like and NOD Receptors by Complementary Antigens as Facilitators of Autoimmune Disease: Review, Model and Novel Predictions

Persistent activation of toll-like receptors (TLR) and nucleotide-binding oligomerization domain-containing proteins (NOD) in the innate immune system is one necessary driver of autoimmune disease (AD), but its mechanism remains obscure. This study compares and contrasts TLR and NOD activation profiles for four AD (autoimmune myocarditis, myasthenia gravis, multiple sclerosis and rheumatoid arthritis) and their animal models. The failure of current AD theories to explain the disparate TLR/NOD profiles in AD is reviewed and a novel model is presented that explains innate immune support of persistent chronic inflammation in terms of unique combinations of complementary AD-specific antigens stimulating synergistic TLRs and/or NODs. The potential explanatory power of the model is explored through testable, novel predictions concerning TLR- and NOD-related AD animal models and therapies.

Sex as a Biological Variable in Atherosclerosis

Atherosclerosis is a chronic inflammatory vascular disease and the predominant cause of heart attack and ischemic stroke. Despite the well-known sexual dimorphism in the incidence and complications of atherosclerosis, there are relatively limited data in the clinical and preclinical literature to rigorously address mechanisms underlying sex as a biological variable in atherosclerosis. In multiple histological and imaging studies, overall plaque burden and markers of inflammation appear to be greater in men than women and are predictive of cardiovascular events. However, while younger women are relatively protected from cardiovascular disease, by the seventh decade, the incidence of myocardial infarction in women ultimately surpasses that of men, suggesting an interaction between sex and age. Most preclinical studies in animal atherosclerosis models do not examine both sexes, and even in those that do, well-powered direct statistical comparisons for sex as an independent variable remain rare. This article reviews the available data. Overall, male animals appear to have more inflamed yet smaller plaques compared to female animals. Plaque inflammation is often used as a surrogate end point for plaque vulnerability in animals. The available data support the notion that rather than plaque size, plaque inflammation may be more relevant in assessing sex-specific mechanisms since the findings correlate with the sex difference in ischemic events and mortality and thus may be more reflective of the human condition. Overall, the number of preclinical studies directly comparing plaque inflammation between the sexes is extremely limited relative to the vast literature exploring atherosclerosis mechanisms. Failure to include both sexes and to address age in mechanistic atherosclerosis studies are missed opportunities to uncover underlying sex-specific mechanisms. Understanding the mechanisms driving sex as a biological variable in atherosclerotic disease is critical to future precision medicine strategies to mitigate what is still the leading cause of death of men and women worldwide.

TLR expression in peripheral monocyte subsets of patients with idiopathic inflammatory myopathies: association with clinical and immunological features

BACKGROUND

Monocytes and toll-like receptors (TLR) have been found in the inflammatory infiltrate of muscle biopsies in patients with idiopathic inflammatory myopathies (IIM), suggesting an important role of these cells in the pathogenesis of myositis. The monocyte subsets, their TLR expression in peripheral blood and their relationship with the clinical characteristics of patients with IIM has not been addressed.

METHODS

We recruited 45 patients with IIM diagnosis and 15 age and sex-adjusted healthy controls. We assessed the disease activity and damage, performed a nailfold capillaroscopy and registered the cardio-pulmonary parameters from the medical charts. Monocyte subsets, their expression of TLR2 and TLR4 and the serum Th1/Th2/Th17 cytokines levels were evaluated by flow cytometry. We expressed quantitative variables as medians and interquartile ranges (IQR) or minimum and maximum (min-max). Differences between groups were assessed with Mann-Whitney U and the Kruskal-Wallis tests. Correlation between quantitative variables was assessed with Spearman Rho.

RESULTS

Twenty-nine patients were women (64.4%) and 32 (71.1%) had dermatomyositis. In comparison to healthy controls, patients with active IIM had a higher percentage of intermediate monocytes and lower amounts of classical monocytes. Patients with IIM had a higher expression of TLR4 in all their monocyte subsets, regardless of disease activity and prednisone treatment. Serum IL-6 correlated with the TLR2 expression in every monocyte subset and the expression of TLR2 in intermediate monocytes was higher among patients with dysphagia. Subjects with nailfold capillaroscopy abnormalities had a higher amount of TLR2+ classical and non-classical monocytes and those with interstitial lung disease (ILD) had a higher percentage of TLR4+ non-classical monocytes. The classical and intermediate monocytes from patients with anti Mi2 antibodies had a higher expression of TLR4. The percentage of intermediate monocytes and the expression of TLR4 in all monocyte subsets showed a good diagnostic capacity in patients with IIM.

CONCLUSION

Patients with IIM have a differential pool of monocyte subsets with an enhanced expression of TLR2 and TLR4, which correlates with disease activity and distinctive clinical features including dysphagia, ILD, vasculopathy, and pro-inflammatory cytokines. These immunological features might be useful as a potential diagnostic tool as well as novel disease activity biomarkers in IIM.

Sex Differences in Systemic Lupus Erythematosus: Epidemiology, Clinical Considerations, and Disease Pathogenesis

Systemic lupus erythematosus (SLE) is a chronic, multiorgan, systemic autoimmune disease that is more common in women than men and is typically diagnosed during reproductive age, necessitating sex-specific considerations in care. In women there is no substantive evidence to suggest that SLE reduces fertility, but subfertility may occur as a result of active disease, immunosuppressive drugs, and age-related declines in fertility related to delays in childbearing. Although pregnancy outcomes have improved, SLE still poses risks in pregnancy that contribute to poorer maternal and fetal outcomes. Cyclophosphamide, an important agent for the treatment of severe or life-threatening lupus, may adversely affect fertility, particularly with increases in dose and patient age. Fertility preservation techniques are therefore an important consideration for women and men before cytotoxic treatment. There is mixed evidence as to whether exogenous estrogen in the form of oral contraceptive pills or hormone replacement therapy may increase the risk for the development of SLE, but among women with SLE already diagnosed, combined oral contraceptive pills and hormone replacement therapy do not confer risk for severe flare and remain important in reproductive care. The higher incidence of SLE in women may nonetheless be attributable to effects of endogenous estrogen, as well as failures in X chromosome inactivation, increased Toll-like receptor gene products, and changes in microRNA function. A greater appreciation of the biological underpinnings and consequences of sex differences in SLE may lead to more targeted treatments and improved outcomes for patients with SLE.

LFA-1 antagonist (BIRT377) similarly reverses peripheral neuropathic pain in male and female mice with underlying sex divergent peripheral immune proinflammatory phenotypes

Aim:

The majority of preclinical studies investigating aberrant glial-neuroimmune actions underlying neuropathic pain have focused on male rodent models. Recently, studies have shown peripheral immune cells play a more prominent role than glial cells in mediating pathological pain in females. Here, we compared the onset and duration of allodynia in males and females, and the anti-allodynic action of a potentially novel therapeutic drug (BIRT377) that not only antagonizes the action of lymphocyte function-associated antigen-1 (LFA-1) to reduce cell migration in the periphery, but may also directly alter the cellular inflammatory bias.

Methods:

Male and female mice were subjected to peripheral nerve injury chronic constriction injury (CCI) applying two methods, using either 4–0 or 5–0 chromic gut suture material, to examine potential sex differences in the onset, magnitude and duration of allodynia. Hindpaw sensitivity before and after CCI and application of intravenous BIRT377 was assessed. Peripheral and spinal tissues were analyzed for protein (multiplex electrochemiluminescence technology) and mRNA expression (quantitative real-time PCR). The phenotype of peripheral T cells was determined using flow cytometry.

Results:

Sex differences in proinflammatory CCL2 and IL-1β and the anti-inflammatory IL-10 were observed from a set of cytokines analyzed. A profound proinflammatory T cell (Th17) response in the periphery and spinal cord was also observed in neuropathic females. BIRT377 reversed pain, reduced IL-1β and TNF, and increased IL-10 and transforming growth factor (TGF)-β1, also an anti-inflammatory cytokine, in both sexes. However, female-derived T cell cytokines are transcriptionally regulated by BIRT377, as demonstrated by reducing proinflammatory IL-17A production with concurrent increases in IL-10, TGF-β1 and the anti-inflammatory regulatory T cell-related factor, FOXP3.

Conclusion:

This study supports that divergent peripheral immune and neuroimmune responses during neuropathy exists between males and females. Moreover, the modulatory actions of BIRT377 on T cells during neuropathy are predominantly specific to females. These data highlight the necessity of including both sexes for studying drug efficacy and mechanisms of action in preclinical studies and clinical trials.

Curcumin attenuates lupus nephritis in MRL/lpr mice by suppressing macrophage-secreted B cell activating factor (BAFF)

This study aimed to investigate the therapeutic effects and mechanism of action of curcumin against a MRL/lpr lupus model. Eight-week-old female MRL/lpr mice were used to establish the lupus nephritis model. Histologic and immunohistochemical analysis was conducted for lupus nephritis. Anti-dsDNA IgG and BAFF level were detected by ELISA. Cells directly isolated from the spleen were used to detect macrophage subsets and activation status by FACS. Curcumin reduced the total IgG and anti-dsDNA IgG levels in blood and reduced the activation of B cells in MRL/lpr mice. Moreover, curcumin prevented activation of macrophages in MRL/lpr mice. Levels of BAFF in serum, spleens and kidneys were also reduced in curcumin-treated MRL/lpr mice. In vitro experiments showed that curcumin reduced the activation of macrophage and leaded to the decrease of BAFF from them upon toll like receptor (TLR) 4 stimulation. Curcumin attenuates lupus nephritis in MRL/lpr mice by inhibiting macrophages activation and their secreting BAFF, which may be a potential therapeutic candidate for the treatment of SLE.

Peripheral myeloid cells contribute to brain injury in male neonatal mice

Background

Neonatal brain injury is increasingly understood to be linked to inflammatory processes that involve specialised CNS and peripheral immune interactions. However, the role of peripheral myeloid cells in neonatal hypoxic-ischemic (HI) brain injury remains to be fully investigated.

Methods

We employed the Lys-EGFP-ki mouse that allows enhanced green fluorescent protein (EGFP)-positive mature myeloid cells of peripheral origin to be easily identified in the CNS. Using both flow cytometry and confocal microscopy, we investigated the accumulation of total EGFP⁺ myeloid cells and myeloid cell subtypes: inflammatory monocytes, resident monocytes and granulocytes, in the CNS for several weeks following induction of cerebral HI in postnatal day 9 mice. We used antibody treatment to curb brain infiltration of myeloid cells and subsequently evaluated HI-induced brain injury.

Results

We demonstrate a temporally biphasic pattern of inflammatory monocyte and granulocyte infiltration, characterised by peak infiltration at 1 day and 7 days after hypoxia-ischemia. This occurs against a backdrop of continuous low-level resident monocyte infiltration. Antibody-mediated depletion of circulating myeloid cells reduced immune cell accumulation in the brain and reduced neuronal loss in male but not female mice.

Conclusion

This study offers new insight into sex-dependent central-peripheral immune communication following neonatal brain injury and merits renewed interest in the roles of granulocytes and monocytes in lesion development.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1344-9) contains supplementary material, which is available to authorized users.

Connecting the immune system, systemic chronic inflammation and the gut microbiome: The role of sex

Unresolved low grade systemic inflammation represents the underlying pathological mechanism driving immune and metabolic pathways involved in autoimmune diseases (AID). Mechanistic studies in animal models of AID and observational studies in patients have found alterations in gut microbiota communities and their metabolites, suggesting a microbial contribution to the onset or progression of AID. The gut microbiota and its metabolites have been shown to influence immune functions and immune homeostasis both within the gut and systematically. Microbial derived-short chain fatty acid (SCFA) and bio-transformed bile acid (BA) have been shown to influence the immune system acting as ligands specific cell signaling receptors like GPRCs, TGR5 and FXR, or via epigenetic processes. Similarly, intestinal permeability (leaky gut) and bacterial translocation are important contributors to chronic systemic inflammation and, without repair of the intestinal barrier, might represent a continuous inflammatory stimulus capable of triggering autoimmune processes. Recent studies indicate gender-specific differences in immunity, with the gut microbiota shaping and being concomitantly shaped by the hormonal milieu governing differences between the sexes. A bi-directional cross-talk between microbiota and the endocrine system is emerging with bacteria being able to produce hormones (e.g. serotonin, dopamine and somatostatine), respond to host hormones (e.g. estrogens) and regulate host hormones' homeostasis (e.g by inhibiting gene prolactin transcription or converting glucocorticoids to androgens). We review herein how gut microbiota and its metabolites regulate immune function, intestinal permeability and possibly AID pathological processes. Further, we describe the dysbiosis within the gut microbiota observed in different AID and speculate how restoring gut microbiota composition and its regulatory metabolites by dietary intervention including prebiotics and probiotics could help in preventing or ameliorating AID. Finally, we suggest that, given consistent observations of microbiota dysbiosis associated with AID and the ability of SCFA and BA to regulate intestinal permeability and inflammation, further mechanistic studies, examining how dietary microbiota modulation can protect against AID, hold considerable potential to tackle increased incidence of AID at the population level.

A new benzenediamine derivative modulates Toll-like receptors-induced myeloid dendritic cells activation and ameliorates lupus-like syndrome in MRLlpr/lpr mice

Modulators of the over-activation of myeloid dendritic cells (mDCs) by Toll-like receptors (TLRs) have an advantage in the treatment of systemic lupus erythematosus (SLE). This study was designed to evaluate the effects of FC-99, a novel benzenediamine derivative, on TLR-induced activation of mDCs, and to assess the efficacy of FC-99 in a murine model of SLE. In vitro, FC-99 inhibited the phenotypic (CD40 and MHC-II) and functional activation (IL-12 and CXCL10) of mDCs induced by TLR ligands. In vivo, MRLlpr/lpr mice displayed renal diseases associated with increased levels of proteinuria and immunoglobulin, which were ameliorated by FC-99. Enhanced accumulation and activation of mDCs in lymphoid organs was also impaired by FC-99. Additionally, FC-99 inhibited the activation of IκB-α and upregulated the expression of TNFα-induced protein 3 (TNFAIP3) in vitro and in vivo. These results indicate that FC-99 modulates TLR-induced activation of mDCs and ameliorates lupus-like syndrome in MRLlpr/lpr mice. This effect is closely associated with the inhibition of IκB-α and upregulation of TNFAIP3.

Toll-like receptor-mediated immune responses in intestinal macrophages; implications for mucosal immunity and autoimmune diseases

Monocytes are precursors of macrophages and key players during inflammation and pathogen challenge in the periphery, whereas intestinal resident macrophages act as innate effector cells to engulf and clear bacteria, secrete cytokines, and maintain intestinal immunity and homeostasis. However, perturbation of toll-like receptor signaling pathway in intestinal macrophages has been associated with tolerance breakdown in autoimmune diseases. In the present review, we have summarized and discussed the role of toll-like receptor signals in human intestinal macrophages, and the role of human intestinal macrophages in keeping human intestinal immunity, homeostasis, and autoimmune diseases.

Elevated expression of miR-142-3p is related to the pro-inflammatory function of monocyte-derived dendritic cells in SLE

Background

Recent studies have shown that alterations in the function of dendritic cells (DCs) are involved in the pathogenesis of systemic lupus erythematosus (SLE). However, the mechanism of the alteration remains unclear.

Methods

We cultured monocyte-derived DCs (moDCs) in vitro and examined the cytokines and chemokines in the supernatants of moDCs in negative controls (NC) and SLE patients in active phase. We then profiled microRNAs (miRNAs) of LPS-stimulated moDCs in SLE patients and used real-time PCR to verify the differentially expressed miRNAs. A lentiviral construct was used to overexpress the level of miR-142-3p in moDCs of NC. We examined the cytokines and chemokines in the supernatants of moDCs overexpressing miR-142-3p and used Transwell test, flow cytometric analysis and cell proliferation to observe the impact on CD4⁺ T cells in moDC-CD4⁺T cell co-culture.

Results

moDCs in patients with SLE secreted increased level of IL-6, CCL2 and CCL5, with attraction of more CD4⁺ T cells compared with NC. We found 18 differentially expressed microRNAs in moDCs of SLE patients by microarray, and target gene prediction showed some target genes of differentially expressed miRNAs were involved in cytokine regulation. miR-142-3p was verified among the highly expressed miRNAs in the SLE group and overexpressing miR-142-3p in moDCs of the NC group caused an increase of SLE-related cytokines, such as CCL2, CCL5, CXCL8, IL-6 and TNF-α. Moreover, moDCs overexpressed with miR-142-3p resulted in attraction of an increased number of CD4⁺ T cells and in suppression of the proportion of Tregs in DC-CD4⁺T cell co-culture whereas the proliferation of CD4⁺T cells was not altered.

Conclusions

The results demonstrated a role for miR-142-3p in regulating the pro-inflammatory function of moDCs in the pathogenesis of SLE. These findings suggested that miR-142-3p could serve as a novel therapeutic target for the treatment of SLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1158-z) contains supplementary material, which is available to authorized users.

Human cells involved in atherosclerosis have a sex

The influence of sex has been largely described in cardiovascular diseases. Atherosclerosis is a complex process that involves many cell types such as vessel cells, immune cells and endothelial progenitor cells; however, many, if not all, studies do not report the sex of the cells. This review focuses on sex differences in human cells involved in the atherosclerotic process, emphasizing the role of sex hormones. Furthermore, we report sex differences and issues related to the processes that determine the fate of the cells such as apoptotic and autophagic mechanisms. The analysis of the data reveals that there are still many gaps in our knowledge regarding sex influences in atherosclerosis, largely for the cell types that have not been well studied, stressing the urgent need for a clear definition of experimental conditions and the inclusion of both sexes in preclinical studies.

A benzenediamine derivate FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting myeloid dendritic cell-secreted BAFF

Myeloid dendritic cells (DCs) can produce B-cell-activating factor (BAFF) that modulates survival and differentiation of B cells and plays a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). Toll-like receptor 4 (TLR4) signaling has important functions in the process of BAFF production. Our previous study showed that a benzenediamine derivate FC-99 possesses anti-inflammation activity and directly interacts with interleukin-1 receptor-associated kinase 4 (IRAK4), which was a pivotal molecule in TLR4 signaling. In this study, we demonstrated that FC-99 attenuated lupus nephritis in the MRL/lpr mice. FC-99 also decreased the levels of total immunoglobulin G (IgG), total IgG2a and IgM in sera, as well as the activation of B cells in the spleens of MRL/lpr mice. Moreover, FC-99 inhibited abnormal activation of myeloid DCs in spleens and reduced the levels of BAFF in sera, spleens, and kidneys of MRL/lpr mice. Furthermore, upon TLR4 stimulation with lipopolysaccharide in vitro, FC-99 inhibited IRAK4 phosphorylation, as well as the activation and BAFF production in murine bone marrow-derived DCs. These data indicate that FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting DC-secreted BAFF, suggesting that FC-99 may be a potential therapeutic candidate for the treatment of SLE.

Tlr2 deficiency does not limit the development of left ventricular hypertrophy in a model of transverse aortic constriction induced pressure overload

Background

Toll-like receptors (TLRs) are involved in a variety of cardiovascular disorders, including septic cardiomyopathy, ischemia/reperfusion, heart failure, and cardiac hypertrophy. Previous research revealed that TLR4 promotes cardiac hypertrophy in vivo. Therefore, we investigated whether TLR2 is also involved in the development of cardiac hypertrophy.

Methods

Tlr2 deficient and wild type mice were subjected to transverse aortic constriction (TAC) or sham operation procedure. Left ventricular, heart and lung weights as well as hemodynamic parameters were determined after 3, 14 or 28 days. Real-time RT PCR was used to evaluate left ventricular gene expression. Protein content was determined via ELISA.

Results

TAC increased systolic left ventricular pressure, contraction and relaxations velocities as well as the heart weight in both genotypes. Tlr2 deficiency significantly enhanced cardiac hypertrophy after 14 and 28 days of TAC. Left ventricular end-diastolic pressure and heart rate increased in Tlr2^−/− TAC mice only. Fourteen days of TAC led to a significant elevation of ANP, BNP, TGFβ and TLR4 mRNA levels in Tlr2^−/− left ventricular tissue.

Conclusion

These data suggest that Tlr2 deficiency may promote the development of cardiac hypertrophy and ventricular remodeling after transverse aortic constriction.

Innate immune receptor Toll-like receptor 4 signalling in neuropsychiatric diseases

The innate immunity is a stereotyped first line of defense against pathogens and unspecified damage signals. One of main actors of innate immunity are the Toll-like receptors (TLRs), and one of the better characterized members of this family is TLR-4, that it is mainly activated by Gram-negative bacteria lipopolysaccharide. In brain, TLR-4 organizes innate immune responses against infections or cellular damage, but also possesses other physiological functions. In the last years, some evidences suggest a role of TLR-4 in stress and stress-related neuropsychiatric diseases. Peripheral and brain TLR-4 activation triggers sickness behavior, and its expression is a risk factor of depression. Some elements of the TLR-4 signaling pathway are up-regulated in peripheral samples and brain post-mortem tissue from depressed and suicidal patients. The "leaky gut" hypothesis of neuropsychiatric diseases is based on the existence of an increase of the intestinal permeability which results in bacterial translocation able to activate TLR-4. Enhanced peripheral TLR-4 expression/activity has been described in subjects diagnosed with schizophrenia, bipolar disorder and in autistic children. A role for TLR-4 in drugs abuse has been also proposed. The therapeutic potential of pharmacological/genetic modulation of TLRs signaling pathways in neuropsychiatry is promising, but a great preclinical/clinical scientific effort is still needed.

SLE: Another Autoimmune Disorder Influenced by Microbes and Diet?

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. Despite years of study, the etiology of SLE is still unclear. Both genetic and environmental factors have been implicated in the disease mechanisms. In the past decade, a growing body of evidence has indicated an important role of gut microbes in the development of autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. However, such knowledge on SLE is little, though we have already known that environmental factors can trigger the development of lupus. Several recent studies have suggested that alterations of the gut microbial composition may be correlated with SLE disease manifestations, while the exact roles of either symbiotic or pathogenic microbes in this disease remain to be explored. Elucidation of the roles of gut microbes - as well as the roles of diet that can modulate the composition of gut microbes - in SLE will shed light on how this autoimmune disorder develops, and provide opportunities for improved biomarkers of the disease and the potential to probe new therapies. In this review, we aim to compile the available evidence on the contributions of diet and gut microbes to SLE occurrence and pathogenesis.

Pentraxin 3 Plasma Levels and Disease Activity in Systemic Lupus Erythematosus

SLE is an autoimmune disorder that involves polyclonal autoimmunity against multiple autoantigens. PTX3, a marker of the acute-phase inflammatory response, plays an important role in innate immunity and in modulation of the adaptive immune response. Our study tried to resolve some rather controversial aspects of the use of PTX3 as a biomarker of disease activity in SLE patients. We demonstrated that plasma PTX3 concentration of the SLE patients was significantly higher than the healthy control groups and reflected disease activity. ROC curve analysis was used to determine best cut-off point (2.8 ng/mL) with a good sensitivity and specificity. In patients with SLE, PTX3 concentrations were correlated with SLEDAI. Trend to remission (TTR) curve was created by plotting PTX3 levels and SLEDAI and we applied the curve as a model for the analysis of two patients with different follow-up. PTX3 plasma levels declined significantly and this decline occurred parallel to the clinical improvement with a complete remission of disease. In patients who experienced a clinical relapse, an increase in PTX3 levels followed the lupus flare. The proposal of PTX3 cut-off associated with TTR and monitoring of PTX3 plasma levels could be an innovative approach to follow-up of SLE patients.

TNF-related weak inducer of apoptosis (TWEAK) levels in schizophrenia

Members of tumor necrosis factor (TNF) superfamily have roles in many biological events and pathogenesis of central nervous system (CNS) diseases. A relatively recently found member of this family, TNF-related weak inducer of apoptosis (TWEAK) have importance both in development of pathological CNS processes and as a target for the treatment of these diseases. The aim of this study was to investigate whether TWEAK's plasma levels are different in patients with schizophrenia. For this purpose plasma TWEAK levels of 44 patients diagnosed with schizophrenia and control group of 40 healthy individuals were compared. Although numerical difference was found between TWEAK levels of patients and controls it was not statistically significant. When we tested for female and male patients and controls seperately, TWEAK levels of male patients were significantly lower than male controls. As far as we know this is the first study that investigates levels of TWEAK in patients with schizophrenia. Although we did not find statistically significant results in our study, we believe that difference could be found in future studies with higher number of subjects. Researches with non-studied TNF superfamily members like TWEAK and TNF-related apoptosis-inducing ligand (TRAIL) could contribute to the understanding of immune-cytokine related hypotheses of schizophrenia.

Sucrose non-fermenting AMPK related kinase/Pentraxin 3 and DNA damage axis: a gateway to cardiovascular disease in systemic lupus erythematosus among Egyptian patients

Background

Systemic lupus erythematosus is a chronic multisystemic autoimmune disease characterized by chronic inflammatory processes and failure of immune-regulatory mechanisms. Systemic lupus erythematosus is associated with increased risk for cardiovascular disease. In view of immunometabolic derangements of systemic lupus erythematosus, we investigated the roles of sucrose non-fermenting AMPK related kinase, Pentraxin 3, and DNA damage in the pathogenesis of systemic lupus erythematosus complicated with cardiovascular disease.

Methods

Forty systemic lupus erythematosus women with cardiovascular disease (systemic lupus erythematosus cases), 40 systemic lupus erythematosus women without cardiovascular disease, and 40 healthy controls were enrolled in this study. Demographic and clinical data were recorded. Plasma concentrations of sucrose non-fermenting AMPK related kinase and Pentraxin 3 were immunoassayed. Carotid intima media thickness, atherogenic, and DNA damage indices were also assessed.

Results

Plasma sucrose non-fermenting AMPK related kinase and Pentraxin 3 concentrations were increased in systemic lupus erythematosus cases with cardiovascular disease compared to systemic lupus erythematosus controls and healthy controls ( P < 0.0001). In systemic lupus erythematosus cases, there was a positive correlation between sucrose non-fermenting AMPK related kinase and Pentraxin 3 (r = 0.57, P < 0.002).

Conclusions

These data highlight a novel role of sucrose non-fermenting AMPK related kinase/Pentraxin 3 axis in systemic lupus erythematosus pathogenesis. Sucrose non-fermenting AMPK related kinase/Pentraxin 3 combined role in immunometabolic signaling and DNA damage response is proposed to accelerate cardiovascular complications in systemic lupus erythematosus patients.