Role of epigenetic regulatory mechanisms in age-related bone homeostasis imbalance.

Alterations to the human organism that are brought about by aging are comprehensive and detrimental. Of these, an imbalance in bone homeostasis is a major outward manifestation of aging. In older adults, the decreased osteogenic activity of bone marrow mesenchymal stem cells and the inhibition of bone marrow mesenchymal stem cell differentiation lead to decreased bone mass, increased risk of fracture, and impaired bone injury healing. In the past decades, numerous studies have reported the epigenetic alterations that occur during aging, such as decreased core histones, altered DNA methylation patterns, and abnormalities in noncoding RNAs, which ultimately lead to genomic abnormalities and affect the expression of downstream signaling osteoporosis treatment and promoter of fracture healing in older adults. The current review summarizes the impact of epigenetic regulation mechanisms on age-related bone homeostasis imbalance.

Micro-Acoustic Holograms for Detachable Microfluidic Devices.

Acoustic microfluidic devices have advantages for diagnostic applications, therapeutic solutions, and fundamental research due to their contactless operation, simple design, and biocompatibility. However, most acoustofluidic approaches are limited to forming simple and fixed acoustic patterns, or have limited resolution. In this study,a detachable microfluidic device is demonstrated employing miniature acoustic holograms to create reconfigurable, flexible, and high-resolution acoustic fields in microfluidic channels, where the introduction of a solid coupling layer makes these holograms easy to fabricate and integrate. The application of this method to generate flexible acoustic fields, including shapes, characters, and arbitrarily rotated patterns, within microfluidic channels, is demonstrated.

First Report on the Trophic Transfer and Priority List of Liquid Crystal Monomers in the Pearl River Estuary.

Liquid crystal monomers (LCMs) are emerging organic pollutants due to their potential persistence, toxicity, and bioaccumulation. This study first characterized the levels and compositions of 19 LCMs in organisms in the Pearl River Estuary (PRE), estimated their bioaccumulation and trophic transfer potential, and identified priority contaminants. LCMs were generally accumulated in organisms from sediment, and the LCM concentrations in all organisms ranged from 32.35 to 1367 ng/g lipid weight. The main LCMs in organisms were biphenyls and analogues (BAs) (76.6%), followed by cyanobiphenyls and analogues (CBAs) (15.1%), and the least were fluorinated biphenyls and analogues (FBAs) (11.2%). The most abundant LCM monomers of BAs, FBAs, and CBAs in LCMs in organisms were 1-(4-propylcyclohexyl)-4-vinylcyclohexane (15.1%), 1-ethoxy-2,3-difluoro-4-(4-(4-propylcyclohexyl) cyclohexyl) benzene (EDPBB, 10.1%), and 4'-propoxy-4-biphenylcarbonitrile (5.1%), respectively. The niche studies indicated that the PRE food web was composed of terrestrial-based diet and marine food chains. Most LCMs exhibited biodilution in the terrestrial-based diet and marine food chains, except for EDPBB and 4,4'-bis(4-propylcyclohexyl) biphenyl (BPCHB). The hydrophobicity, position of fluorine substitution of LCMs, and biological habits may be important factors affecting the bioaccumulation and trophic transfer of LCMs. BPCHB, 1-(prop-1-enyl)-4-(4-propylcyclohexyl) cyclohexane, and EDPBB were characterized as priority contaminants. This study first reports the trophic transfer processes and mechanisms of LCMs and the biomonitoring in PRE.

[Latest Findings on the Role of RUNX1 in Bone Development and Disorders]. / RUNX1åœ¨éª¨å‘è‚²åŠéª¨ç›¸å ³ç–¾ç— ä¸­çš„ä½œç”¨ç ”ç©¶è¿›å±•.

Runt-related transcription factor (RUNX1) is a transcription factor closely involved in hematopoiesis. RUNX1 gene mutation plays an essential pathogenic role in the initiation and development of hematological tumors, especially in acute myeloid leukemia. Recent studies have shown that RUNX1 is also involved in the regulation of bone development and the pathological progression of bone-related diseases. RUNX1 promotes the differentiation of mesenchymal stem cells into chondrocytes and osteoblasts and modulates the maturation and extracellular matrix formation of chondrocytes. The expression of RUNX1 in mesenchymal stem cells, chondrocytes, and osteoblasts is of great significance for maintaining normal bone development and the mass and quality of bones. RUNX1 also inhibits the differentiation and bone resorptive activities of osteoclasts, which may be influenced by sexual dimorphism. In addition, RUNX1 deficiency contributes to the pathogenesis of osteoarthritis, delayed fracture healing, and osteoporosis, which was revealed by the RUNX1 conditional knockout modeling in mice. However, the roles of RUNX1 in regulating the hypertrophic differentiation of chondrocytes, the sexual dimorphism of activities of osteoclasts, as well as bone loss in diabetes mellitus, senescence, infection, chronic inflammation, etc, are still not fully understood. This review provides a systematic summary of the research progress concerning RUNX1 in the field of bone biology, offering new ideas for using RUNX1 as a potential target for bone related diseases, especially osteoarthritis, delayed fracture healing, and osteoporosis.

Bacillus anthracis Edema Toxin Inhibits Efferocytosis in Human Macrophages and Alters Efferocytic Receptor Signaling.

The Bacillus anthracis Edema Toxin (ET), composed of a Protective Antigen (PA) and the Edema Factor (EF), is a cellular adenylate cyclase that alters host responses by elevating cyclic adenosine monophosphate (cAMP) to supraphysiologic levels. However, the role of ET in systemic anthrax is unclear. Efferocytosis is a cAMP-sensitive, anti-inflammatory process of apoptotic cell engulfment, the inhibition of which may promote sepsis in systemic anthrax. Here, we tested the hypothesis that ET inhibits efferocytosis by primary human macrophages and evaluated the mechanisms of altered efferocytic signaling. ET, but not PA or EF alone, inhibited the efferocytosis of early apoptotic neutrophils (PMN) by primary human M2 macrophages (polarized with IL-4, IL-10, and/or dexamethasone) at concentrations relevant to those encountered in systemic infection. ET inhibited Protein S- and MFGE8-dependent efferocytosis initiated by signaling through MerTK and αVß5 receptors, respectively. ET inhibited Rac1 activation as well as the phosphorylation of Rac1 and key activating sites of calcium calmodulin-dependent kinases CamK1α, CamK4, and vasodilator-stimulated phosphoprotein, that were induced by the exposure of M2(Dex) macrophages to Protein S-opsonized apoptotic PMN. These results show that ET impairs macrophage efferocytosis and alters efferocytic receptor signaling.

Defective selection of thymic regulatory T cells accompanies autoimmunity and pulmonary infiltrates in Tcra-deficient mice double transgenic for human La/Sjögren's syndrome-B and human La-specific TCR.

A human La/Sjögren's syndrome-B (hLa)-specific TCR/hLa neo-self-Ag double-transgenic (Tg) mouse model was developed and used to investigate cellular tolerance and autoimmunity to the ubiquitous RNA-binding La Ag often targeted in systemic lupus erythematosus and Sjögren's syndrome. Extensive thymic clonal deletion of CD4(+) T cells occurred in H-2(k/k) double-Tg mice presenting high levels of the I-E(k)-restricted hLa T cell epitope. In contrast, deletion was less extensive in H-2(k/b) double-Tg mice presenting lower levels of the epitope, and some surviving thymocytes were positively selected as thymic regulatory T cells (tTreg). These mice remained serologically tolerant to hLa and healthy. H-2(k/b) double-Tg mice deficient of all endogenous Tcra genes, a deficiency known to impair Treg development and function, produced IgG anti-hLa autoantibodies and displayed defective tTreg development. These autoimmune mice had interstitial lung disease characterized by lymphocytic aggregates containing Tg T cells with an activated, effector memory phenotype. Salivary gland infiltrates were notably absent. Thus, expression of nuclear hLa Ag induces thymic clonal deletion and tTreg selection, and lymphocytic infiltration of the lung is a consequence of La-specific CD4(+) T cell autoimmunity.

Peptidoglycan from Bacillus anthracis Inhibits Human Macrophage Efferocytosis in Part by Reducing Cell Surface Expression of MERTK and TIM-3.

Bacillus anthracis peptidoglycan (PGN) is a major component of the bacterial cell wall and a key pathogen-associated molecular pattern contributing to anthrax pathology, including organ dysfunction and coagulopathy. Increases in apoptotic leukocytes are a late-stage feature of anthrax and sepsis, suggesting there is a defect in apoptotic clearance. In this study, we tested the hypothesis that B. anthracis PGN inhibits the capacity of human monocyte-derived macrophages (MΦ) to efferocytose apoptotic cells. Exposure of CD163+CD206+ MΦ to PGN for 24 h impaired efferocytosis in a manner dependent on human serum opsonins but independent of complement component C3. PGN treatment reduced cell surface expression of the proefferocytic signaling receptors MERTK, TYRO3, AXL, integrin αVß5, CD36, and TIM-3, whereas TIM-1, αVß3, CD300b, CD300f, STABILIN-1, and STABILIN-2 were unaffected. ADAM17 is a major membrane-bound protease implicated in mediating efferocytotic receptor cleavage. We found multiple ADAM17-mediated substrates increased in PGN-treated supernatant, suggesting involvement of membrane-bound proteases. ADAM17 inhibitors TAPI-0 and Marimastat prevented TNF release, indicating effective protease inhibition, and modestly increased cell-surface levels of MerTK and TIM-3 but only partially restored efferocytic capacity by PGN-treated MΦ. We conclude that human serum factors are required for optimal recognition of PGN by human MΦ and that B. anthracis PGN inhibits efferocytosis in part by reducing cell surface expression of MERTK and TIM-3.

Physiology of pregnancy and oral local anesthesia considerations.

Background: Safe and effective local anesthesia is a prerequisite for emergency oral surgeries and most dental treatments. Pregnancy is characterized by complex physiological changes, and increased sensitivity to pain. Pregnant women are particularly vulnerable to oral diseases, such as caries, gingivitis, pyogenic granuloma and third molar pericoronitis. Maternally administered drugs can affect the fetus through the placenta. Therefore, many physicians and patients are reluctant to provide or accept necessary local anesthesia, which leads to delays in the condition and adverse consequences. This review is intended to comprehensively discuss the instructions for local anesthesia in the oral treatment of pregnant patients. Methodology: An in-depth search on Medline, Embase, and the Cochrane Library was performed to review articles concerned with maternal and fetal physiology, local anesthetic pharmacology, and their applications for oral treatment. Results: Standard oral local anesthesia is safe throughout the pregnancy. At present, 2% lidocaine with 1:200,000 epinephrine is considered to be the anesthetic agent that best balances safety and efficacy for pregnant women. Maternal and fetal considerations must be taken into account to accommodate the physiological and pharmacological changes in the gestation period. Semi-supine position, blood pressure monitoring, and reassurance are suggested for high-risk mothers to reduce the risk of transient changes in blood pressure, hypoxemia, and hypoglycemia. For patients with underlying diseases, such as eclampsia, hypertension, hypotension, and gestational diabetes, the physicians should use epinephrine cautiously and control the dose of anesthetic. New local anesthesia formulations and equipment, which contribute to minimizing injection pain and relieving the anxiety, have and are being developed but remain understudied. Conclusions: Understanding the physiological and pharmacological changes during pregnancy is essential to ensure the safety and efficiency of local anesthesia. Optimal outcomes for the mother and fetus hinge on a robust understanding of the physiologic alterations and the appropriate selection of anesthetic drugs and approaches.

Dynamic Regulation of Ferroptosis by Lipid Metabolism.

Significance: Ferroptosis is featured by the accumulation of polyunsaturated-lipid peroxidation on cellular membranes in an iron-dependent manner. Ferroptosis has been implicated in various pathophysiological processes, including cancer, neurodegeneration, and ischemia-reperfusion tissue injury. However, our understanding about the dynamic and context-specific regulation of ferroptosis remains incomplete. Recent Advances: As the major substrate for peroxidation, the cellular lipidome regulates ferroptosis sensitivity and execution by controlling the abundance and availability of polyunsaturated-lipids for peroxidative modifications. In turn, the cellular lipidome is regulated by a complex network of enzymes and transporters, as well as upstream layers of receptors, kinases, and transcription factors. A number of research has shed light on the link between lipid metabolism and ferroptosis. Here, we summarize our current knowledge on the role of the lipidome and associated protein regulators in various stages of ferroptosis, ranging from initiation, execution to cell death evasion by cells experiencing ferroptotic stress. Critical Issues: This review provides an overview of the mechanisms underlying lipid peroxidation and ferroptosis by discussing the lipid species that directly contribute to lipid peroxidation and ferroptosis, how cells regulate the abundances of these pro-ferroptosis lipids, how lipid peroxidation causes cell death, and how cells prevent and repair membrane lipid damage under ferroptotic conditions. Future Directions: Cell fate regulation in vivo could be different from in vitro culture settings. We envision that a comprehensive and detailed understanding about these important questions in the dynamic regulation of ferroptosis in vivo will accelerate our development of ferroptosis-targeted therapies to improve human health.

Exposure to essential and non-essential trace elements and risks of congenital heart defects: A narrative review.

Congenital heart defects (CHDs) are congenital abnormalities involving the gross structures of the heart and large blood vessels. Environmental factors, genetic factors and their interactions may contribute to the pathogenesis of CHDs. Generally, trace elements can be classified into essential trace elements and non-essential trace elements. Essential trace elements such as copper (Cu), zinc (Zn), iron (Fe), selenium (Se), and manganese (Mn) play important roles in human biological functions such as metabolic function, oxidative stress regulation, and embryonic development. Non-essential trace elements such as cadmium (Cd), arsenic (As), lead (Pb), nickle (Ni), barium (Ba), chromium (Cr) and mercury (Hg) are harmful to health even at low concentrations. Recent studies have revealed the potential involvement of these trace elements in the pathogenesis of CHDs. In this review, we summarized current studies exploring exposure to essential and non-essential trace elements and risks of CHDs, in order to provide further insights for the pathogenesis and prevention of CHDs.

Peptidoglycan from Bacillus anthracis Inhibits Human Macrophage Efferocytosis in Part by Reducing Cell Surface Expression of MERTK and TIM-3.

Bacillus anthracis peptidoglycan (PGN) is a major component of the bacterial cell wall and a key pathogen-associated molecular pattern (PAMP) contributing to anthrax pathology, including organ dysfunction and coagulopathy. Increases in apoptotic lymphocytes are a late-stage feature of anthrax and sepsis, suggesting there is a defect in apoptotic clearance. Here, we tested the hypothesis that B. anthracis PGN inhibits the capacity of human monocyte-derived macrophages (MΦ) to efferocytose apoptotic cells. Exposure of CD163+CD206+ MΦ to PGN for 24h impaired efferocytosis in a manner dependent on human serum opsonins but independent of complement component C3. PGN treatment reduced cell surface expression of the pro-efferocytic signaling receptors MERTK, TYRO3, AXL, integrin αVß5, CD36 and TIM-3, whereas TIM-1, αVß3, CD300b, CD300f, STABILIN-1 and STABILIN-2 were unaffected. ADAM17 is a major membrane-bound protease implicated in mediating efferocytotic receptor cleavage. We found multiple ADAM17-mediated substrates increased in PGN-treated supernatant suggesting involvement of membrane-bound proteases. ADAM17 inhibitors TAPI-0 and Marimastat prevented TNF release, indicating effective protease inhibition, and modestly increased cell-surface levels of MerTK and TIM-3 but only partially restored efferocytic capacity by PGN-treated MΦ. We conclude that human serum factors are required for optimal recognition of PGN by human MΦ and that B. anthracis PGN inhibits efferocytosis in part by reducing cell surface expression of MERTK and TIM-3.

Association between Maternal Selenium Exposure and Congenital Heart Defects in Offspring: A Systematic Review and Meta-Analysis.

Background: The association between congenital heart defects (CHDs) and selenium (Se) is still unclear. We aimed to systematically review and quantitative analyze the potential relationship between maternal Se exposure and CHDs in the offspring. Methods: PubMed, Embase, Web of Science and Scopus databases were searched from inception up to August 2021 for relevant studies. Methodological quality of the studies was assessed through Newcastle-Ottawa scale. The Standard mean difference (SMD) and corresponding 95% confidence interval (CI) were calculated to compare maternal Se levels between CHDs groups and control groups using a random-effects model. Results: Four articles covering five studies were included in the systematic review, and three articles covering four studies were included in the meta-analysis. One study measured Se concentrations in maternal hair and found a positive correlation between high concentrations and increased risk of CHDs in offspring. However, one study on cord blood, and one on whole blood illustrated that Se exposure was associated with decreased risk of CHDs. There was no significant association found between serum Se levels and CHDs in two studies. Pooled results showed decreased Se levels in the circulation of mothers with CHDs offspring (SMD = -108.27, 95% CI: -192.72, -23.82), with statistically significant heterogeneity (I2 = 99.8%, P < 0.001) but not in hair, as compared with controls. Conclusion: Low maternal Se status may be associated with increased risk of CHDs in offspring. However, further larger-scale studies with strict and consistent design methods are still required to investigate this issue.

Corrigendum: Role of the CXCL13/CXCR5 axis in autoimmune diseases.

[This corrects the article DOI: 10.3389/fimmu.2022.850998.].

Elevated CXCL13 in primary Sjögren's syndrome and its correlation with disease activity: a systematic review and meta-analysis.

OBJECTIVES: CXCL13 levels have been reported to be elevated in primary Sjögren's syndrome (pSS) patients. This study investigated alterations involving the CXCL13/CXCR5 axis in pSS patients and explored the correlation between CXCL13 expression and disease severity. METHODS: Six databases, including PubMed, Web of Science, Embase, Ovid Medline, China National Knowledge Infrastructure, and Wanfang, were searched. The quality of the included studies was assessed using the Newcastle-Ottawa Scale criteria. We analyzed CXCL13 concentrations in the serum and saliva of pSS patients and healthy controls (HCs). Next, we analyzed the percentage of CXCR5+CD4+ T cells among CD4+ T cells in pSS patients and HCs. Correlations between CXCL13 levels and serological, clinical, and histological parameters of patients were also assessed. Publication bias was determined using funnel plots and Egger's test. RESULTS: Twenty-three articles were included; of these, 14 studies reported CXCL13 levels, and 5 reported CXCR5+CD4+ T cell count of pSS patients and HCs. Nine articles covering 32 studies reported correlations between serum CXCL13 levels and serological, clinical, and histological parameters in pSS patients. Expressions of CXCL13 and CXCR5+CD4+ T cell count were significantly increased in pSS patients compared with those in HCs. There was a positive correlation between CXCL13 levels and serum IgG levels, disease activity indices, and focus score in minor salivary gland biopsy of patients. CONCLUSIONS: CXCL13 abundance was evidently elevated in pSS patients and correlated with disease activity and can therefore probably be employed as a robust biomarker to monitor and diagnose pSS. Key Points • Serum CXCL13 is significantly elevated in primary Sjögren's syndrome patients. • CXCL13 level correlates with disease severity and activity of primary Sjögren's syndrome. • CXCL13 can probably be used as a robust biomarker to monitor and diagnose primary Sjögren's syndrome.

Oxidative stress and inflammation regulation of sirtuins: New insights into common oral diseases.

Sirtuins are a family of nicotinamide adenine dinucleotide (NAD)+-dependent histone deacetylases, comprising seven members SIRT1-SIRT7. Sirtuins have been extensively studied in regulating ageing and age-related diseases. Sirtuins are also pivotal modulators in oxidative stress and inflammation, as they can regulate the expression and activation of downstream transcriptional factors (such as Forkhead box protein O3 (FOXO3a), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB)) as well as antioxidant enzymes, through epigenetic modification and post-translational modification. Most importantly, studies have shown that aberrant sirtuins are involved in the pathogenesis of infectious and inflammatory oral diseases, and oral cancer. In this review, we provide a comprehensive overview of the regulatory patterns of sirtuins at multiple levels, and the essential roles of sirtuins in regulating inflammation, oxidative stress, and bone metabolism. We summarize the involvement of sirtuins in several oral diseases such as periodontitis, apical periodontitis, pulpitis, oral candidiasis, oral herpesvirus infections, dental fluorosis, and oral cancer. At last, we discuss the potential utilization of sirtuins as therapeutic targets in oral diseases.

Role of the CXCL13/CXCR5 Axis in Autoimmune Diseases.

CXCL13 is a B-cell chemokine produced mainly by mesenchymal lymphoid tissue organizer cells, follicular dendritic cells, and human T follicular helper cells. By binding to its receptor, CXCR5, CXCL13 plays an important role in lymphoid neogenesis, lymphoid organization, and immune responses. Recent studies have found that CXCL13 and its receptor CXCR5 are implicated in the pathogenesis of several autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, primary Sjögren's syndrome, myasthenia gravis, and inflammatory bowel disease. In this review, we discuss the biological features of CXCL13 and CXCR5 and the recent findings on the pathogenic roles of the CXCL13/CXCR5 axis in autoimmune diseases. Furthermore, we discuss the potential role of CXCL13 as a disease biomarker and therapeutic target in autoimmune diseases.

Fine Structure of the Visual System of Arge similis (Hymenoptera, Argidae).

External morphology and ultrastructure of the visual system of Arge similis (Vollenhoven, 1860) adults were investigated by light microscopy, scanning electron microscopy, and transmission electron microscopy. Each compound eye contains 2022 ± 89 (mean ± SE) facets in males and 2223 ± 52 facets in females. Arge similis has an apposition kind of compound eye composed of a cornea, a crystalline cone of four cone cells, and a centrally fused rhabdom made up of the rhabdomeres of eight large retinular cells. Each crystalline cone is surrounded by primary and secondary pigment cells with black spherical screening pigment granules measuring 0.60 ± 0.02 and 0.41 ± 0.01 µm in diameter, respectively. Based on our findings, the compound eye of A. similis can be expected to exhibit high adaptability to light intensity changes.

Metallo-alginate hydrogel can potentiate microwave tumor ablation for synergistic cancer treatment.

Microwave ablation (MWA) as a local tumor ablation strategy suffers from posttreatment tumor recurrence. Development of adjuvant biomaterials to potentiate MWA is therefore of practical significance. Here, the high concentration of Ca2+ fixed by alginate as Ca2+-surplus alginate hydrogel shows enhanced heating efficiency and restricted heating zone under microwave exposure. The high concentration of extracellular Ca2+ synergizes with mild hyperthermia to induce immunogenic cell death by disrupting intracellular Ca2+ homeostasis. Resultantly, Ca2+-surplus alginate hydrogel plus MWA can ablate different tumors on both mice and rabbits at reduced operation powers. This treatment can also elicit antitumor immunity, especially if synergized with Mn2+, an activator of the stimulation of interferon genes pathway, to suppress the growth of both untreated distant tumors and rechallenged tumors. This work highlights that in situ-formed metallo-alginate hydrogel could act as microwave-susceptible and immunostimulatory biomaterial to reinforce the MWA therapy, promising for clinical translation.

Preparation of CdS@C Photocatalyst Using Phytoaccumulation Cd Recycled From Contaminated Wastewater.

Cadmium is one of the most toxic heavy metal contaminants in soils and water bodies and poses a serious threat to ecosystems and humans. However, cadmium is also an important resource widely used in many industries. The recovery of cadmium in the form of high-value products is considered as an ideal disposal strategy for Cd-contaminated environments. In this work, Pistia stratiotes was used to recycle cadmium from wastewaters through phytoaccumulation and then transformed into carbon-supported cadmium sulfide photocatalyst (CdS@C) through carbonization and hydrothermal reaction. The CdS@C photocatalyst contained a mixture of cubic and hexagonal CdS with lower band gap energy (2.14 eV) and high electron-hole separation efficiency, suggesting an excellent photoresponse ability and photocatalytic efficiency. The impressive stability and photocatalytic performance of CdS@C were demonstrated in efficient photodegradation of organic pollutants. •OH and O2•- were confirmed as the major active species for organic pollutants degradation during CdS@C photocatalysis. This work provides new insights into addressing Cd contaminated water bodies and upcycling in the form of photocatalyst.

Toll-like receptor 7 (TLR7) modulates anti-nucleosomal autoantibody isotype and renal complement deposition in mice exposed to syngeneic late apoptotic cells.

OBJECTIVES: The objectives of this study were to determine whether late apoptotic cell material directly induces autoantibodies characteristic of systemic lupus erythematosus (SLE) and to investigate the innate recognition pathways involved. METHODS: B6, B6.MyD88(-/-), B6.TLR7(-/-) and B6.TLR9(-/-) mice were subcutaneously injected with B6 syngeneic late apoptotic thymocytes (SLATs) without adjuvant on days 0, 10, 24 and 37. Sera were tested for IgG antibodies to histones and double-stranded DNA (dsDNA) by ELISA and Crithidia luciliae indirect immunofluorescence. IgG and C3 deposition in kidney glomeruli was assessed by immunostaining and fluorescence microscopy. RESULTS: SLAT injections induced anti-dsDNA and anti-histone antibodies of the IgG1 and IgG2b isotypes in B6 but not MyD88(-/-) mice. TLR7(-/-) and TLR9(-/-) mice injected with SLATs produced delayed or slightly more robust responses, respectively. SLAT injections induced IgG deposits in renal glomeruli of B6, TLR7(-/-) and TLR9(-/-) mice that were absent in MyD88(-/-) mice. Unlike B6 and TLR9(-/-) animals, TLR7(-/-) mice failed to exhibit IgG colocalised glomerular C3 deposits and demonstrated autoantibodies of primarily the IgG2a isotype. CONCLUSIONS: Late apoptotic cell-induced anti-histone and anti-dsDNA antibodies require MyD88 but not Toll-like receptor (TLR)9. Moreover, TLR7 promotes glomerular C3 deposition, possibly through a mechanism of altered antibody isotype switching.