Titanium Ions Promote Exogenous Calcium-Dependent Calcium Influx in Activated Jurkat T Cells: A Possible Mechanism to Explain Its Immunostimulatory Properties

Tumor-derived interleukin-1 receptor antagonist exhibits immunosuppressive functions and promotes pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) is a pernicious disease characterized by an immunosuppressive milieu that is unresponsive to current immunotherapies. Interleukin-1 receptor antagonist (IL-1Ra) is a natural anti-inflammatory cytokine; however, its contribution to cancer pathogenesis and immunosuppression remains elusive. In this research, we investigated the role and mechanism of IL-1Ra in malignant progression of PDA.

RESULTS

Through analyzing clinical dataset and examining the pathological tumor tissues and serum samples, we have demonstrated that IL-1Ra expression is elevated in human PDA and positively associated with malignant progression of PDA. To study the biological function of IL-1Ra in tumors, we generated a set of mouse pancreatic cancer cell lines with a knockout (KO) of the Il1rn gene, encoding IL-1Ra, and compared the tumor growth rates in immune-competent and immune-deficient mice. We found that the Il1rn KO cells exhibited greater tumor inhibition in immune-competent mice, highlighting the crucial role of a functional immune system in Il1rn KO-mediated anti-tumor response. Consistently, we found an increase in CD8+ T cells and a decrease in CD11b+Ly6G- immunosuppressive mononuclear population in the tumor microenvironment of Il1rn KO-derived tumors. To monitor the inhibitory effects of IL-1Ra on immune cells, we utilized a luciferase-based reporter CD4+ T cell line and splenocytes, which were derived from transgenic mice expressing ovalbumin-specific T cell receptors in CD8+ T cells, and mice immunized with ovalbumin. We showed that IL-1Ra suppressed T cell receptor signaling and inhibited antigen-specific interferon-γ (IFN-γ) secretion and cytolytic activity in splenocytes.

CONCLUSIONS

Our findings illustrate the immunosuppressive properties of the natural anti-inflammatory cytokine IL-1Ra, and provide a rationale for considering IL-1Ra-targeted therapies in the treatment of PDA.

Weighted Gene Coexpression Network Analysis Identified IL2/STAT5 Signaling Pathway as an Important Determinant of Peri-Implantitis

Objective

Peri-implantitis (PI) is one of the main reasons for dental implant failure. Until now, the etiology and pathogenesis of PI remain unclear.

Methods

In this study, we used differentially expressed genes (DEGs) analysis and gene function enrichment analysis to assess the expression profile of peri-implant bone tissue and gingiva in PI public data from the Gene Expression Omnibus (GEO) database. Then, we used gingival tissues from patients with PI and healthy individual to construct gene coexpression networks to reveal the biological functions of the genes in PI using RNA sequencing data. Afterward, key gene modules were selected to reveal the critical biological process or signaling pathway using Hallmark's gene enrichment and expression analysis of the related pathway members in PI.

Results

DEGs were enriched in the formation of cellular responses to external stimuli in bone tissue. Cytokine production, lymphocyte activation, immune response-regulating signaling pathway, and blood vessel development were the top GO biology process or pathways of the DEGs in gingival tissue. Weighted gene coexpression network analysis (WGCNA) of RNA-seq data was used to assess the results of correlation analysis between modules and traits and correlation analysis between modules and functions. kMEpurple, kMEgreen, and kMEred modules were selected as the key gene modules. Signaling pathways and gene expression analysis were performed on selected modules, such as IL2/STAT5 signaling pathway, TNFα signaling pathway via NFκB, and angiogenesis were enriched in kMEpurple module. Hedgehog signaling pathway, Wnt β-catenin signaling pathway, and IL2/STAT5 signaling pathway were enriched in kMEgreen module. Peroxisome, IL2/STAT5 signaling pathway, and epithelial-mesenchymal transformation process were enriched in kMEred module. All the enrichment results of key modules contained IL2/STAT5 signaling pathway. Conclusion. Differential gene and enrichment analysis based on public data showed differences in gene expression patterns and biological process between bone and gingival tissues in PI. This spatial-temporal heterogeneity is reflected in the formation of cellular responses to external stimuli, which was enriched in bone tissue, but cytokine production, lymphocyte activation, immune response regulating signaling pathway, and blood vessel development were enriched in gingival tissue. WGCNA and Hallmark gene sets enrichment analysis of the gingival tissue expression profile and showed that IL2-mediated activation of immune cells could be a critical mechanism in PI. As a new clinical treatment alternative, we suggest that IL2/STAT5 pathway blockers could be helpful in the treatment of PI.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Alterations to Titanium Surface Depending on the Fluorides and Abrasives in Toothpaste

Fluoride and abrasives in toothpastes may cause corrosion and deterioration of the titanium used for implants and other prostheses. The purpose of this study was to investigate how the presence or absence and types of fluoride and abrasives affected the titanium surface texture. Brushing with toothpastes was performed on pure-titanium discs using an abrasive testing machine. Unprocessed titanium discs without brushing were used as control samples. Surface roughness, color, and gloss of titanium were measured and the differences compared with the control were analyzed. Additionally, titanium surfaces and abrasives in toothpastes were observed using a scanning electron microscope to compare the surface texture of each sample. Some toothpastes (abrasive+) significantly increased the difference in surface roughness, color, and gloss, compared with ultrapure water. Toothpaste (fluoride+/abrasive+) that had many polygonal abrasive particles led to the largest color differences and exhibited notable scratches and a larger number of contaminant- or corrosion-like black spots. In contrast, brushing with toothpaste without fluoride or abrasives (fluoride-/abrasive-) caused little change to the titanium surface. These results suggest that both fluoride and abrasives in toothpaste used for brushing may be factors that affect surface texture and corrosion resistance of titanium.

Role of the Hippo-YAP/NF-κB signaling pathway crosstalk in regulating biological behaviors of macrophages under titanium ion exposure

The presence of metal ions, such as titanium (Ti) ions, is toxic to adjacent tissues of implants. Indeed, Ti ions may induce an inflammatory response through the NF-κB pathway, thus causing damage to soft and hard tissues. The involvement of Yes-associated protein (YAP), a key factor of the Hippo pathway, in an immuno-inflammatory response has been confirmed, whereas its role in Ti ion-mediated inflammation has not been elucidated. Therefore, this study aimed to investigate the role of signal crosstalk between the Hippo/YAP and NF-κB signaling pathways in the pro-inflammatory effect of Ti ions on macrophages. In our work, RAW264.7 cells were cocultured with Ti ions. The migration capacity of macrophages under Ti ion exposure was measured by transwell assay. Western blot analysis was used to detect the expressions of related proteins. Polymerase chain reaction was used to evaluate the expression of pro-inflammatory cytokines. The nucleus translocation of YAP and P65 was visualized and analyzed via immunofluorescence staining. The results showed that the migration of macrophages was promoted under Ti ion exposure. Ten parts per million Ti ions induced nuclear expression of YAP and activated the NF-κB pathway, which finally upregulated the expression of pro-inflammatory cytokines in macrophages. Moreover, the inhibition of the NF-κB pathway rescued the reduction of YAP expression under Ti ion exposure. Most importantly, the overexpression of YAP exacerbated the inflammatory response mediated by Ti ions through the NF-κB pathway. In summary, this study explored the mechanism of Hippo-YAP/NF-κB pathway crosstalk involved in the regulation of macrophage behaviors under Ti ion exposure.

LncRNA-mediated ceRNA network was identified as a crucial determinant of differential effects in periodontitis and periimplantitis by high-throughput sequencing

BACKGROUND AND OBJECTIVE

Although periimplantitis and periodontitis share similar features, particularly clinical features, they are two different diseases and should be analyzed separately. Thus far, few omics-level differences in periimplantitis and periodontitis have been reported. This study was aimed at exploring the differential effects of expression mRNAs, lncRNAs, and miRNAs in periodontitis and periimplantitis by high-throughput sequencing and competitive endogenous RNA (ceRNA) analysis.

METHODS

Gingival tissues of healthy individuals (HI) and periimplantitis (PI) and periodontitis (P) patients were collected and used for genome-wide sequencing. The differentially expressed genes (DEGs) were screened and visualized by R software. The functions and pathways of DEGs were analyzed using Metascape, and the ceRNA network was constructed using the Cytoscape software. Finally, gene set enrichment analysis (GSEA) was used to predict the function of key nodes in ceRNA.

RESULTS AND CONCLUSION

By constructing the regulated ceRNA network, six genes (FAM126B, SORL1, PRLR, CPEB2, RAP2C, and YOD1) and 16 miRNAs (hsa-miR-338-5p, hsa-miR-650, hsa-miR-9-5p, hsa-miR-1290, hsa-miR-544a, hsa-miR-3179, hsa-miR-1269a, hsa-miR-3679-5p, hsa-miR-149-5p, hsa-miR-615-3p, hsa-miR-33b-5p, hsa-miR-31-5p, hsa-miR-4639-5p, hsa-miR-204-5p, hsa-miR-5588-5p, and hsa-mir-196a-5p) were detected. Five long non-coding RNAs (lnc-CORO2B-1, lnc-MBL2-7, lnc-TRIM45-1, lnc-CHST10-2, and lnc-TNP1-6) were found to target these miRNAs in this ceRNA network. The ceRNA network based on transcriptome data revealed that FAM126B, SORL1, PRLR, CPEB2, RAP2C, and YOD1 were crucial proteins of differential effects in periodontitis and periimplantitis. The lncRNA-miRNA-mRNA interaction involved the regulation of the Hippo signaling pathway, Wnt signaling pathway, Toll-like receptor signaling pathway, NOD signaling pathway, oxidative stress, and innate immune process. These regulated pathways and biological processes may be factors contributing to the pathogenesis of periimplantitis being distinct from that of periodontitis.

Do Battlefield Injury-acquired Indwelling Metal Fragments Induce Metal Immunogenicity?

BACKGROUND

A battlefield-related injury results in increased local and systemic innate immune inflammatory responses, resulting in wound-specific complications and an increased incidence of osteoarthritis. However, little is known about whether severe injuries affect long-term systemic homeostasis, for example, immune function. Moreover, it also remains unknown whether battlefield-acquired metal fragments retained over the long term result in residual systemic effects such as altered immune reactivity to metals.

QUESTIONS/PURPOSES

Does a retained metal fragment from a battlefield injury contribute to increased (1) adaptive metal-specific immune responses, (2) systemically elevated metal ion serum levels, and (3) serum immunoglobulin levels compared with combat injuries that did not result in a retained metal fragment?

METHODS

In this pilot study, we analyzed metal-immunogenicity in injured military personnel and noninjured control participants using lymphocyte transformation testing (LTT, lymphocyte proliferation responses to cobalt, chromium and nickel challenge at 0.001, 0.01 and 0.1-mM concentrations in triplicate for each participant), serum metal ion analysis (ICP-mass spectroscopy), and serum immunoglobulin analysis (IgE, IgG, IgA, and IgM ). Military personnel with a battlefield-sustained injury self-recruited without any exclusion for sex, age, degree of injury. Those with battlefield injury resulting in retained metal fragments (INJ-FRAG, n = 20 male, mean time since injury ± SD was 12 ± 10 years) were compared with those with a battlefield injury but without retained metal fragments (INJ-NO-FRAG, n = 12 male, mean time since injury ± SD was 13 ± 12 years). A control group comprised of male noninjured participants was used to compare measured immunogenicity metrics (n = 11, males were selected to match battlefield injury group demographics).

RESULTS

Military participants with sustained metal fragments had increased levels of metal-induced lymphocyte responses. The lymphocyte stimulation index among military participants with metal fragments was higher than in those with nonretained metal fragments (stimulation index = 4.2 ± 6.0 versus stimulation index = 2.1 ± 1.2 (mean difference 2.1 ± 1.4 [95% confidence interval 5.1 to 0.8]; p = 0.07) and an average stimulation index = 2 ± 1 in noninjured controls. Four of 20 participants injured with retained fragments had a lymphocyte proliferation index greater than 2 to cobalt compared with 0 in the group without a retained metal fragment or 0 in the control participants. However, with the numbers available, military personnel with retained metal fragments did not have higher serum metal ion levels than military participants without retained metal fragment-related injuries or control participants. Military personnel with retained metal fragments had lower serum immunoglobulin levels (IgG, IgA, and IgM) than military personnel without retained metal fragments and noninjured controls, except for IgE. Individuals who were metal-reactive positive (that is, a stimulation index > 2) with retained metal fragments had higher median IgE serum levels than participants who metal-reactive with nonmetal injuries (1198 ± 383 IU/mL versus 171 ± 67 IU/mL, mean difference 1027 ± 477 IU/mL [95% CI 2029 to 25]; p = 0.02).

CONCLUSIONS

We found that males with retained metal fragments after a battlefield-related injury had altered adaptive immune responses compared with battlefield-injured military personnel without indwelling metal fragments. Military participants with a retained metal fragment had an increased proportion of group members and increased average lymphocyte reactivity to common implant metals such as nickel and cobalt. Further studies are needed to determine a causal association between exposure to amounts of retained metal fragments, type of injury, personnel demographics and general immune function/reactivity that may affect personal health or future metal implant performance.

LEVEL OF EVIDENCE

Level IV, therapeutic study.