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Background As Japan's population continues to age, it is estimated that the number of people aged ≥75 years will exceed 20 million by 2025. Furthermore, over the past 10 years, we have not reduced the difference between life expectancy and healthy life expectancy. Therefore, the extension of healthy life expectancy and the development of a healthy society are the most urgent issues. In terms of medical care, the changing times have inevitably led to changes in disease structures and medical demands; therefore, the medical delivery system has had to be changed to meet these demands. As dementia rapidly increases, it is important to address "frailty," a condition in which people become more vulnerable to environmental factors as they age, and there is a need to provide services to older people, particularly the old-old, that emphasize quality of life in addition to medical care. To realize a super-aged society that will remain vigorous and vibrant for many years, we need to rethink the future of Japanese medicine and healthcare, and the state of society. Current situation and problems Disparity between healthy life expectancy and average life expectancy in the realization of a healthy society It is a challenge to build a society with a long and healthy life expectancy through comprehensive prevention and management of lifestyle-related diseases, as well as the elucidation of the factors that explain sex differences in healthy life expectancy, based on the recognition that lifestyle-related diseases in midlife are risk factors for frailty and dementia in old age. Challenges in medical care for building a super-aged and healthy society The challenges include promoting clinical guidelines suitable for older people, including lifestyle-related disease management, promoting comprehensive research on aging (basic research, clinical research and community collaboration research), and embodying a paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care." Furthermore, the key to the future of integrated community care is the development of a comprehensive medical care system for older people in each region and the development of the next generation of medical personnel. Dissemination of frailty prevention measures in a super-aged society The concept of frailty encompasses the meaning of multifacetedness and reversibility; therefore, a comprehensive approach is required, including the renewal of conventional prevention activities in each region, such as the nutritional status of older people, physical activity including exercise, and various opportunities for social participation and participation conditions. Challenges of an unstable diet and undernutrition in older people According to the National Health and Nutrition Examination Survey of Japan, energy and protein intakes are low in Japanese people aged ≥75 years; particularly in people aged ≥80 years, low and insufficient intake of nutrients are prominent. Undernutrition in older people is increasing and is more pronounced in women. There are multiple factors behind this, including social factors, such as living alone, eating alone, poverty and other social factors, as well as problems with access to food security. Pharmacotherapy for older people: measures against polypharmacy In addition to the problems of adverse drug events, drug interactions, duplication of effects and the presence of drugs that "require particularly careful administration," it is also necessary to take measures against polypharmacy in older people, as well as medical economic issues, such as high drug costs and large amounts of remaining drugs. Barriers to this measure include multiple medical institution visits for each disease, lack of coordination between professions, and lack of understanding by patients and families. Role of local communities in a healthy society The decline in the working-age population is also a major challenge; however, we need to make a shift to use this declining birthrate and aging population as an opportunity rather than a crisis. As we look ahead to the coming of the 100-year age of life, we rethink the creation of a comprehensive society and community, and aim to create an age-free society where everyone can play an active role and live in peace, regardless of age. Contents of the proposal In this report, we have put together a vision for the future of an aging Japanese society from a broader perspective of how the environment and local communities should be, rather than simply from the perspective of individual health. We aim to convey this proposal to the Ministry of Health, Labor and Welfare, the Ministry of Education, Culture, Sports, Science and Technology, the Cabinet Office, and various professional organizations. The paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care" should be promoted for the development of a healthy society While further promoting pre-emptive medical care in the medical care for older people, the development of multidisciplinary medical guidelines appropriate for older people should be promoted at the same time. In addition, we should promote basic aging research, clinical research (including the long-term care field) and transitional research that cover regional areas. Furthermore, while promoting the paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care," the development of various comprehensive medical treatment systems for older people and the strengthening of integrated community care systems should be promoted. Development of the next generation of medical personnel to comprehensively deal with geriatric care, including training geriatric specialists, should be promoted As the number of older people with multimorbidities and frailty rapidly increases in the future, we should promote the development of the next generation of medical personnel who can comprehensively handle medical care for older people, including training leading geriatricians in cooperation with multiple professions in the integrated community care system to provide sufficient medical care. Countermeasures for frailty in older people should be promoted from medical and community planning perspectives To address frailty, which requires comprehensive evaluation and intervention, the three pillars of frailty prevention (nutrition, exercise and social participation) should be incorporated and addressed as part of community development within each municipality, taking into account local characteristics. In particular, it is necessary to revise the way of thinking about nutrition management in older people and the guidelines of the societies in the field. In addition, it is important to strengthen industry-academia-government-private partnerships in each region, taking into account not only medical issues, but also social factors, and encourage the development of momentum in the entire region regarding measures against undernutrition in older people. Polypharmacy measures should be promoted in pharmacotherapy for older people It is necessary to promote cooperation between physicians and pharmacists, establish other multiprofessional cooperation systems, and develop medical and long-term care insurance systems to support this. It is also essential to change the public's mindset, and awareness-raising activities at all levels are required, including the enhancement of educational materials for medical caregivers and the general public. In addition, the economic impact of healthcare using big data should be timely clarified. Innovation in medical and urban planning perspectives should be promoted In the future, it will be necessary to modify and update multidisciplinary approaches such as social participation (e.g. participation in a salon) with a view to innovation in both medical care and community development, especially on the idea of a symbiotic community. In addition, industry-academia-government-private partnership is necessary, including all aforementioned, such as places where people can play an active role in the rest of their lives (such as employment), promotion of human connections, promotion of technology to support older people and support for daily life. Geriatr Gerontol Int 2021; 21: 601-613.

Objective To avoid risk of infections associated with dental implants, thermal oxidation processes for practical dental Ti alloys were studied for both high bonding strength and antibacterial properties in visible light. Methods Two-step thermal oxidation, comprising carburization (first step of treatment: in Ar-1%CO gas) and subsequent oxidation (second step of treatment: in air), was conducted on commercially pure (CP) Ti, Ti-6Al-4V (Ti64), and Ti-6Al-7Nb (Ti67) alloys to form TiO2 layers. Their bonding strengths and antibacterial properties against Escherichia coli (E. coli) in visible light (λ ≥ 400 nm) were evaluated. Results TiO2 layers formed on each metal were composed of anatase and/or rutile. Anatase fraction and carbon concentration in the layers decreased with increasing temperature in the second step of treatment. Antibacterial properties of the TiO2 layers were dependent on the temperature in the second step of treatment. An approximate antibacterial activity value of 2 (killing ∼99% bacteria) was obtained when the temperatures in the second step of treatment were 673 and 773 K for CP Ti, 773 K for Ti64, and 773 and 873 K for Ti67. It was found that the TiO2 layer must contain carbon and be anatase-rich to exhibit excellent antibacterial properties. Bonding strength between the substrate and TiO2 layers formed at 773 K in the second step of treatment exceeded 80 MPa and was independent of substrate type. Significance TiO2 layers, possessing both high bonding strength and excellent antibacterial properties, were successfully formed on practical dental Ti alloys via two-step thermal oxidation.

Morphogenesis and differentiation of organs is required for subsequent functional maturation. The morphological features of Peyer's patches vary among species. In pigs, they develop extensively in the ileum as ileal Peyer's patches (IPPs). However, the role of IPPs in the porcine immune system remains to be elucidated because of a lack of complete understanding of IPP organogenesis. Results of the present study revealed that development of porcine IPPs is initiated prenatally between embryonic days 76 and 91. The process of IPP organogenesis is concomitant with increased transcriptional patterns of CXCL13 and CCL19. IPPs undergo further development postnatally by forming central, marginal, and subepithelial zones. Importantly, a large number of proliferating B cells and apoptotic cells are found in porcine IPPs postnatally, but not prenatally. The expression level of IgM in proliferating B cells depends on the zone in which distinct B cells are separately localized after birth. Specifically, IgM+ cells are predominantly found in the central zone, whereas IgM-/low cells are abundant in the marginal zone. Importantly, the cellular feature of IPPs differs from that of mesenteric lymph nodes (MLNs) where such distinct zones are not formed both prenatally and postnatally. Our findings suggest that IPPs (not MLNs) in postnatal pigs are involved in complementing functions of the primary lymphoid tissue that promotes the differentiation and maturation of B cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection induces severe pneumonia and is the cause of a worldwide pandemic. Coronaviruses, including SARS-CoV-2, have RNA proofreading enzymes in their genomes, resulting in fewer gene mutations than other RNA viruses. Nevertheless, variants of SARS-CoV-2 exist and may induce different symptoms; however, the factors and the impacts of these mutations are not well understood. We found that there is a bias to the mutations occurring in SARS-CoV-2 variants, with disproportionate mutation to uracil (U). These point mutations to U are mainly derived from cytosine (C), which is consistent with the substrate specificity of host RNA editing enzymes, APOBECs. We also found the point mutations which are consistent with other RNA editing enzymes, ADARs. For the C-to-U mutations, the context of the upstream uracil and downstream guanine from mutated position was found to be most prevalent. Further, the degree of increase of U in SARS-CoV-2 variants correlates with enhanced production of cytokines, such as TNF-a and IL-6, in cell lines when compared with stimulation by the ssRNA sequence of the isolated virus in Wuhan. Therefore, RNA editing is a factor for mutation bias in SARS-CoV-2 variants, which affects host inflammatory cytokines production.

Rutile TiO2 layers were formed on substrates of Ti-(0-10)at%Au alloys by a simple process of air oxidation, and their antibacterial activities were evaluated under visible-light irradiation (λ ≥ 400 nm). Au was introduced into the TiO2 layers on Ti-(1-10)at%Au alloys and existed as both metallic Au nanoparticles and dissolved Au3+ ions. The TiO2 layers that formed on Ti-5at%Au and Ti-10at%Au alloys exhibited visible-light photocatalytic activity, that is, degradation of stearic acid and antibacterial activity against Escherichia coli. These visible-light activities were attributed to the surface plasmon resonance of metallic Au nanoparticles and the decrease in bandgap energy caused by dissolved Au3+ ions. The formation of hydroxyl radicals observed under visible-light irradiation is attributable to antibacterial activity. From a cost perspective, a Ti-5at%Au alloy is more suitable as a substrate for the formation of a TiO2 layer with antibacterial properties than a Ti-10at%Au alloy. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 991-1000, 2019.

In vitro dissolution and antibacterial activity of Ag nanoparticle-containing hydroxyapatite (HA) powders (AgNPHAP) synthesized by precipitation method were evaluated in this study. AgNPHAP were immersed in Tris-HCl solution with 30 mM Cl ions to estimate the in vitro dissolution behavior. The amount of Ag ions in Tris-HCl solution first increased and then decreased because Ag ions reacted with Cl ions to form AgCl. The antibacterial activity of AgNPHAP increased with increasing amounts of AgNPs attached to the HA powders in both 1/500 nutrient broth (NB) and undiluted NB solutions, which had Cl ion concentrations of 0.2 and 100 mM, respectively. These results indicate that HA powders as Ag nanoparticle carriers can effectively prevent bacterial infections despite AgCl precipitation, even under simulated biological conditions such as in undiluted NB solution.

To avoid risk of infections associated with dental implants, thermal oxidation processes for practical dental Ti alloys were studied for both high bonding strength and antibacterial properties in visible light.Two-step thermal oxidation, comprising carburization (first step of treatment: in Ar-1%CO gas) and subsequent oxidation (second step of treatment: in air), was conducted on commercially pure (CP) Ti, Ti-6Al-4V (Ti64), and Ti-6Al-7Nb (Ti67) alloys to form TiOTiOTiO

Nickel ions (Ni2+) eluted from biomedical devices cause inflammation and Ni allergy. Although Ni2+ and Co2+ elicit common effects, Ni2+ induces a generally stronger inflammatory reaction. However, the molecular mechanism by which Ni2+ and Co2+ induce such different responses remains to be elucidated. In the present study, we compared the effects of Ni2+ and Co2+ on the expression of interleukin (IL)-8 in human monocyte THP-1 cells. We report that NiCl2 but not CoCl2 induced the expression of IL-8; in contrast, CoCl2 elicited a higher expression of hypoxia-inducible factor-1α (HIF-1α). The NiCl2-induced expression of IL-8 in late phase was blocked by a HIF-1α inhibitor, PX-478, indicating that NiCl2 targets additional factors responsible for activating HIF-1α. To identify such targets, proteins that bound preferentially to Ni-NTA beads were analyzed by LC/MS/MS. The analysis yielded heat shock protein 90β (HSP90β) as a possible candidate. Furthermore, Ni2+ reduced the interaction of HSP90β with HIF-1α, and instead promoted the interaction between HIF-1α and HIF-1β, as well as the nuclear localization of HIF-1α. Using various deletion variants, we showed that Ni2+ could bind to the linker domain on HSP90β. These results suggest that HSP90β plays important roles in Ni2+-induced production of IL-8 and could be a potential target for the regulation of Ni2+-induced inflammation.

Development of bioceramics with antibacterial activity and without cytotoxicity would be beneficial for preventing infection associated with implants. This study aimed to capitalize on the antibacterial properties of silver (Ag) incorporated in or coexisting in metallic form with calcium phosphates (CaPs). The in vitro dissolution behavior, antibacterial activity, and cytotoxicity of Ag-containing CaPs with different phase fractions of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) were evaluated. The antibacterial activity of Ag-containing CaPs depended on the main phase of CaP, the chemical state of Ag, and the amount of incorporated Ag. Superior antibacterial activity was obtained from sustained release of Ag ions through continuous dissolution of Ag-incorporated β-TCP compared to that obtained for HA coexisting with metallic Ag particles. Ag-containing CaPs did not exhibit any toxic effect on V79 fibroblasts. Thus, these results demonstrated the effectiveness of Ag-incorporated β-TCP in preventing infection, with respect to long-term applications.

Genetic evolution that occurs during cancer progression enables tumour heterogeneity, thereby fostering tumour adaptation, therapeutic resistance and metastatic potential. Immune responses are known to select (immunoedit) tumour cells displaying immunoevasive properties. Here we address the role of IFN-γ in mediating the immunoediting process. We observe that, in several mouse tumour models such as HA-expressing 4T1 mammary carcinoma cells, OVA-expressing EG7 lymphoma cells and CMS5 MCA-induced fibrosarcoma cells naturally expressing mutated extracellular signal-regulated kinase (ERK) antigen, the action of antigen-specific cytotoxic T cell (CTL) in vivo results in the emergence of resistant cancer cell clones only in the presence of IFN-γ within the tumour microenvironment. Moreover, we show that exposure of tumours to IFN-γ-producing antigen-specific CTLs in vivo results in copy-number alterations (CNAs) associated with DNA damage response and modulation of DNA editing/repair gene expression. These results suggest that enhanced genetic instability might be one of the mechanisms by which CTLs and IFN-γ immunoedits tumours, altering their immune resistance as a result of genetic evolution., T cell mediated anti-tumour immune responses result in the emergence of an immune-resistant population in a process called immunoediting. Here, the authors show that immunoediting is associated with an increase in genomic rearrangements of tumour cells that requires both cytotoxic T cells and IFNγ exposure.

Because of its corrosion resistance palladium (Pd) has been widely used in many consumer products ranging from fashion accessories to dental materials. Recently, however, an increase in Pd allergy cases has been reported. Metal allergy is categorized as a Type IV allergy, which is characterized as a delayed-type hypersensitivity reaction in which T cells are known to play an important role; however, the precise mechanism of their action remains unclear. Here we defined the relationship between histamine and the Pd allergic reaction specifically with respect to T cell responses. To verify the effects of histamine on T cells, we examined whether there is a change in IFN-γ production following stimulation of histamine or the antihistamine, olopatadine hydrochloride (OLP), in vitro . In addition, we assessed whether OLP administration affected the degree of footpad swelling or IFN-γ production during the Pd allergy response in mice. We found that histamine stimulation increased IFN-γ production in T cells, specifically enhancing IFN-γ production in CD8 + T cells compared with CD4 + T cells. Interestingly, OLP suppressed the production of IFN-γ in CD8 + T cells, and this compound inhibited footpad swelling and IFN-γ production in mice with Pd allergy. These results suggest that histamine promotes the Type IV allergic reaction and thus, the histamine 1 receptor (H1R) might be useful therapeutic target for treatment of metal allergy.

Chromium (Cr) is commonly added into various metal alloys to improve some mechanical properties such as corrosion resistance, strength, and workability. However, Cr is also known to be a metal allergen for some individuals. Metal allergy is a T cell-mediated disease with symptoms of inflammation and swelling that involve inflammatory cytokines and prostaglandins. Hence, suppressing these inflammation paths by using COX-2 inhibitor might be useful in treating Cr allergy. In this study, mice were used with Cr-induced allergy challenge model. The mice were injected with celecoxib once per day for 7 days one hour after the challenge. Footpad samples were stained with haematoxylin and eosin (H&E), and lymphocytes were isolated from popliteal lymph nodes for the flow cytometric analysis. The results show that both prostaglandin E2 (PGE2), a known mediator of inflammation, and cyclooxygenases (COX)-2 have important roles in the development of Cr allergy. Further, COX-2 inhibitor, celecoxib, was effective in relieving swelling and inflammation in Cr-allergic mice concordant with suppression of IFN-γ production by CD8+ T cells and T cell accumulation in the lymph nodes. Therefore, the inhibition of COX-2 may be a therapeutic target for Cr allergy, and additional molecules in the PGE2 signalling pathway may also be an effective therapeutic target for the treatment of metal allergy.

Rutile TiO

Nickel (Ni) eluted from metallic biomaterials is widely accepted as a major cause of allergies and inflammation. To improve the safety of cobalt-chromium-molybdenum (Co-Cr-Mo) alloy implants, new ultralow-Ni Co-Cr-Mo alloys with and without zirconium (Zr) have been developed, with Ni contents of less than 0.01%. In the present study, we investigated the biocompatibility of these new alloys in vivo by subcutaneously implanting pure Ni, conventional Co-Cr-Mo, ultralow-Ni Co-Cr-Mo, and ultralow-Ni Co-Cr-Mo with Zr wires into the dorsal sides of mice. After 3 and 7 days, tissues around the wire were excised, and inflammation; the expression of IL-1β, IL-6, and TNF-α; and Ni, Co, Cr, and Mo ion release were analyzed using histological analyses, qRT-PCR, and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Significantly larger amounts of Ni eluted from pure Ni wires than from the other wires, and the degree of inflammation depended on the amount of eluted Ni. Although no significant differences in inflammatory reactions were identified among new alloys and conventional Co-Cr-Mo alloys in histological and qRT-PCR analyses, ICP-MS analysis revealed that Ni ion elution from ultralow-Ni Co-Cr-Mo alloys with and without Zr was significantly lower than from conventional Co-Cr-Mo alloys. Our study, suggests that the present ultralow-Ni Co-Cr-Mo alloys with and without Zr have greater safety and utility than conventional Co-Cr-Mo alloys. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1505-1513, 2016.

The transcriptional regulator IκB-ζ is important for the control of apoptosis in keratinocytes. Thus, IκB-ζ-deficient mice develop autoimmune diseases, such as Sjögren’s syndrome. However, T cells also play a pivotal role in Sjögren’s syndrome. To study the role of IκB-ζ in T cells, we generated T cell-specific, IκB-ζ-deficient mice. We observed increased numbers of peripheral effector/memory CD4+ cells and IFN-γ-producing CD4+ cells in 3-week-old mice. We found that IκB-ζ can be up-regulated by TGF-β1 in naϊve CD4+ T cells and that it negatively regulates IFN-γ expression. In addition, we generated Treg-specific, IκB-ζ deficient mice and found that IκB-ζ is dispensable for the plasticity and stability of Tregs. However, Tregs from T cell-specific, IκB-ζ-deficient mice have reduced immunoregulatory function. Thus, our data reveal a previously unappreciated role for IκB-ζ in IFN-γ production in T cells and the immunoregulatory function of Tregs.

Nickel ions (Ni2+) are eluted from various metallic materials, such as medical devices implanted in human tissues. Previous studies have shown that Ni2+ enters inflammatory cells inducing inflammation. However, the regulation of Ni2+ uptake in cells has not yet been reported in detail. In the present study, we investigated the effects of various divalent cations on Ni2+ uptake and Ni2+-induced interleukin (IL)-8 production in the human monocytic cell line, THP-1. We demonstrated that ZnCl2, MnCl2, and CoCl2 inhibited the Ni2+ uptake, while CuCl2, FeCl2, MgCl2, and divalent metal transporter (DMT)-1 inhibitor, Chlorazol Black, did not. Furthermore, ZnCl2 inhibited Ni2+-induced IL-8 production, correlating with the inhibition of Ni2+ uptake. These results suggested that Ni2+ uptake occurred through Zn2+, Mn2+, and Co2+-sensitive transporters and that the inhibition of Ni2+ uptake resulted in the inhibition of IL-8 production. Furthermore, using an Ni wire-implanted mouse model, we found that Ni wire-induced expression of mouse macrophage inflammatory protein-2 (MIP-2) and cyclooxygenase-2 (COX-2) mRNA in the skin tissue surrounding the wire were enhanced by low Zn conditions. These results suggested that the physiological concentration of Zn2+ modulates Ni2+ uptake by inflammatory cells, and a Zn deficient state might increase sensitivity to Ni.

While metallic biomaterials have led to an improvement in the quality of life, metal allergies, especially to palladium (Pd), has caused a recent increase in allergic patients. Metal allergy is known to be a T cell-mediated delayed-type hypersensitivity (DTH); however, the pathogenic T cell subsets and the specific T cell receptor (TCR) have not been identified. Therefore, we attempted to identify the pathogenic T cells responsible for Pd allergy. We found that activating CD8+ T cells significantly increased and that the TRAV (TCRα variable) 7-2*02 chain skewed in Pd allergic mice. Furthermore, adoptive transfer experiments revealed that in vitro-cultured Pd-stimulated antigen presenting cells (APCs) function as memory APCs with recipient mice developing Pd allergy and that the frequency of TRAV7-2*02 increases the same as conventional Pd allergic mice. In contrast, neither proliferation of CD8+ T cells nor increasing of TRAV7-2*02 was observed in major histocompatibility complex I (MHC I)-deficient Pd-APCs transferred to mice. Taken together, we revealed that TRAV7-2*02-expressing CD8+ T cells are the pathogenic T cells for the development of Pd allergy. We also identified the CDR3 consensus motif of pathogenic TCRs as CAAXSGSWQLIF in TRAV7-2*02/TRAJ (TCRα junction)22*01 positive cells. These results suggest that the specific TCRs represent novel targets for the development of diagnostics and treatments for metal allergy.

The natural killer group 2 membrane D (NKG2D) activating receptor plays crucial roles not only in host defense against tumors and viral infections, but also in autoimmune diseases. After NKG2D-mediated activation, Natural killer (NK) cells must be regulated to avoid potentially harmful reactivity. However, the negative regulation of these activated NK cells is poorly understood. Here, we reveal that the engagement of NKG2D by its ligand elicits not only target cell lysis, but also NK cell fratricide. Conventional mouse NK cells underwent cell death when cocultured with RMA cells expressing the NKG2D ligand retinoic acid early-inducible protein 1 (Rae-1), but not with RMA cells lacking MHC class I. NK cells from mice deficient for DAP10 and DAP12 or perforin did not undergo death, highlighting the importance of the NKG2D pathway for NK cell death. However, NKG2D does not transmit direct death signals in NK cells. Rather, the interaction between NKG2D and Rae-1 allowed NK cells to acquire tumor-derived Rae-1 by a membrane transfer process known as ”trogocytosis,” which was associated with clathrin-dependent NKG2D endocytosis. NK cells dressed with Rae-1 were lysed by neighboring NK cells through the NKG2D-induced perforin pathway in vitro and in vivo. These results provide the unique NKG2D function in negative regulation of activated NK cells.

Osteopontin (Opn), a multifunctional extracellular matrix protein, is implicated in the pathogenesis of various inflammatory disorders. Under physiologic conditions, its expression is restricted to certain tissues including bone and kidney tubule. However, cellular activation during disease development induces Opn expression in various immune cells. In this study, using Opn-EGFP knock-in (KI) mice we found that CD8α⁺ T cells in the intestinal tissues, including Peyer’s patch, lamina propria and epithelium, express Opn under steady state conditions. Therefore, we examined the role of Opn-expressing CD8α⁺ T cells in intestinal homeostasis. Interestingly, Opn knockout (KO) mice had altered fecal microflora concordant with a reduction of TCRγδ⁺ intraepithelial lymphocytes (IELs). Consistent with this result, both treatment with anti-Opn blocking antibody and deficiency of Opn resulted in decreased survival of TCRγδ⁺ and TCRαβ⁺ IELs. This data suggests that a possibility that Opn may function as a survival factor for IELs in the intestinal tissue. Collectively, these data suggest the possibility that Opn might regulate the homeostasis of intestinal microflora through maintenance of TCRγδ⁺ IELs, possibly by support of IEL survival.

In this chapter, bioceramic coatings on Ti and its alloys are examined. Surface modification processes of metallic biomaterials are reviewed, and the formation and evaluation of amorphous calcium phosphate (ACP) and anatase-rich TiO2 coatings are described. Dry processes such as radio-frequency (RF) magnetron sputtering and thermal oxidation are employed for coating. Ag-containing ACP coating films exhibited antibacterial activity through the continuous release of Ag ions, caused by the resorbability of ACP. Anatase-rich TiO2 layers fabricated by a two-step thermal oxidation process showed photodegradation of organic compounds under both UV- and visible-light irradiation. The introduction of Au into TiO2 layers from Ti-Au alloy substrates by thermal oxidation contributed to the expression of visible-light response.

Bronchiolitis obliterans after lung transplantation is a major cause of postoperative mortality in which T cell-mediated immunity is known to play an important role. However, the exact contribution of natural killer (NK) cells, which have functions similar to CD8+ T cells, has not been defined. Here, we assessed the role of NK cells in murine bronchiolitis obliterans through heterotopic tracheal transplantations and found a greater percentage of NK cells in allografts than in isografts. Depletion of NK cells using an anti-NK1.1 antibody attenuated bronchiolitis obliterans in transplant recipients compared with controls. In terms of NK cell effector functions, an improvement in bronchiolitis obliterans was observed in perforin-KO recipient mice compared to wild type (WT). Furthermore, we found upregulation of NKG2D-ligand in allografts and demonstrated the significance of this using grafts expressing Rae-1, a murine NKG2D-ligand, which induced severe bronchiolitis obliterans in WT and Rag-1 KO recipients. This effect was ameliorated by injection of anti-NKG2D blocking antibody. Together, these results suggest that cytotoxicity resulting from activation of NK cells through NKG2D leads to the development of murine bronchiolitis obliterans.

The innate immune system has developed to acquire a wide variety of pattern-recognition receptors (PRRs) to identify potential pathogens, whereas pathogens have also developed to escape host innate immune responses. ITIM-bearing receptors are attractive targets for pathogens to attenuate immune responses against them; however, the in vivo role of the inhibitory PRRs in host–bacteria interactions remains unknown. We demonstrate in this article that Staphylococcus aureus, a major Gram-positive bacteria, exploits inhibitory PRR paired Ig-like receptor (PIR)-B on macrophages to suppress ERK1/2 and inflammasome activation, and subsequent IL-6 and IL-1β secretion. Consequently, Pirb−/− mice infected with S. aureus showed enhanced inflammation and more effective bacterial clearance, resulting in resistance to the sepsis. Screening of S. aureus mutants identified lipoteichoic acid (LTA) as an essential bacterial cell wall component required for binding to PIR-B and modulating inflammatory responses. In vivo, however, an LTA-deficient S. aureus mutant was highly virulent and poorly recognized by macrophages in both wild-type and Pirb−/− mice, demonstrating that LTA recognition by PRRs other than PIR-B mediates effective bacterial elimination. These results provide direct evidence that bacteria exploit the inhibitory receptor for virulence, and host immune system counterbalances the infection.

CD30+ lymphoproliferative disorders represent a spectrum of diseases from lymphomatoid papulosis (LyP) to primary cutaneous anaplastic large-cell lymphoma (PCALCL) (1, 2). LyP is characterized by recurrent papulonodular lesions, which undergo spontaneous regression (1, 2). Survival is unaffected by LyP, but patients are at risk of a second cutaneous or lymphoid malignancy (1). PCALCL has a favourable prognosis with a 5-year survival rate between 76% and 96%. In this report, we used immunohistochemical (IHC) staining of LyP type A and PCALCL specimens to examine for macrophage markers as well as dendritic cell (DC)-specific markers and their functional markers.

Natural killer (NK) cells contribute to not only innate but also to adaptive immunity by interacting with dendritic cells (DCs) and T cells. All activated human NK cells express HLA-DR and can initiate MHCII-dependent CD4 + T-cell proliferation; however, the expression of MHCII by mouse NK cells and its functional significance are controversial. In this study, we show that NK–DC interactions result in the emergence of MHCII-positive NK cells. Upon in vitro or in vivo activation, mouse conventional NK cells did not induce MHCII transcripts, but rapidly acquired MHCII protein from DCs. MHCII H2-Ab1 –deficient NK cells turned I-A b -positive when adoptively transferred into wild-type mice or when cultured with WT splenic DCs. NK acquisition of MHCII was mediated by intercellular membrane transfer called “trogocytosis,” but not upon DAP10/12- and MHCI-binding NK cell receptor signaling. MHCII-dressed NK cells concurrently acquired costimulatory molecules such as CD80 and CD86 from DCs; however, their expression did not reach functional levels. Therefore, MHCII-dressed NK cells inhibited DC-induced CD4 + T-cell responses rather than activated CD4 + T cells by competitive antigen presentation. In a mouse model for delayed-type hypersensitivity, adoptive transfer of MHCII-dressed NK cells attenuated footpad swelling. These results suggest that MHCII-dressed NK cells generated through NK–DC interactions regulate T cell-mediated immune responses.

Inducible nitric-oxide synthase (iNOS, NOS2) plays a prominent role in macrophage bactericidal and tumoricidal activities. A relatively large amount of NO produced via iNOS, however, also targets the macrophage itself for apoptotic cell death. To uncover the intrinsic mechanisms of iNOS regulation, we have characterized the SPRY domain- and SOCS box-containing protein 1 (SPSB1), SPSB2, and SPSB4 that interact with the N-terminal region of iNOS in a D-I-N-N-N sequence-dependent manner. Fluorescence microscopy revealed that these SPSB proteins can induce the subcellular redistribution of iNOS from dense regions to diffused expression in a SOCS box-dependent manner. In immunoprecipitation studies, both Elongin C and Cullin-5, components of the multi-subunit E3 ubiquitin ligase, were found to bind to iNOS via SPSB1, SPSB2, or SPSB4. Consistently, iNOS was polyubiquitinated and degraded in a proteasome-dependent manner when SPSB1, SPSB2, or SPSB4 was expressed. SPSB1 and SPSB4 had a greater effect on iNOS regulation than SPSB2. The iNOS N-terminal fragment (residues 1-124 of human iNOS) could disrupt iNOS-SPSB interactions and inhibit iNOS degradation. In lipopolysaccharide-treated macrophages, this fragment attenuated iNOS ubiquitination and substantially prolonged iNOS lifetime, resulting in a corresponding increase in NO production and enhanced NO-dependent cell death. These results not only demonstrate the mechanism of SPSB-mediated iNOS degradation and the relative contributions of different SPSB proteins to iNOS regulation, but also show that iNOS levels are sophisticatedly regulated by SPSB proteins in activated macrophages to prevent overproduction of NO that could trigger detrimental effects, such as cytotoxicity.

Background Two types of atopic dermatitis (AD) have been proposed, with different pathophysiological mechanisms underlying this seemingly heterogeneous disorder. The extrinsic type shows high IgE levels presumably as a consequence of skin barrier damage and feasible allergen permeation, whereas the intrinsic type exhibits normal IgE levels and is not mediated by allergen-specific IgE. Objectives To investigate the relationship between pruritus perception threshold and skin barrier function of patients with AD in a comparison between the extrinsic and intrinsic types. Methods Enrolled in this study were 32 patients with extrinsic AD, 17 with intrinsic AD and 24 healthy individuals. The barrier function of the stratum corneum was assessed by skin surface hydration and transepidermal water loss (TEWL), and pruritus perception was evaluated by the electric current perception threshold (CPT) of sensory nerves upon neuroselective transcutaneous electric stimulation. Results Skin surface hydration was significantly lower and TEWL was significantly higher in extrinsic AD than intrinsic AD or normal controls. Although there was no statistically significant difference in CPT among extrinsic AD, intrinsic AD and normal controls, CPT was significantly correlated with skin surface hydration and inversely with TEWL in intrinsic AD and normal controls, but not extrinsic AD. Finally, CPT was correlated with the visual analogue scale of itch in the nonlesional skin of patients with extrinsic but not intrinsic AD. Conclusions Patients with extrinsic AD have an impaired barrier, which increases the pre-existing pruritus but rather decreases sensitivity to external stimuli. In contrast, patients with intrinsic AD retain a normal barrier function and sensory reactivity to external pruritic stimuli.